@tannx what driver are you using? For your video card, the nvidia binary blob from 310.xx to 340.xx is recomended (not 343.xx or newer)

@Tele42

This' my nvidia driver.

and I remenber the launcher didn't got problem, last time I install steam on debian jessie without nvidia video card driver.

I am having a similiar issue.
The launcher also crashed when I click on the button "LOGIN TO AN EXISTING ACCOUNT"

steam
Running Steam on linuxmint 17 64-bit
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(1411443970)
Installing breakpad exception handler for appid(steam)/version(1411443970)
Installing breakpad exception handler for appid(steam)/version(1411443970)
Installing breakpad exception handler for appid(steamwebhelper)/version(20140922201705)
Installing breakpad exception handler for appid(steamwebhelper)/version(1411417025)
[0925/162904:ERROR:nss_util.cc(1018)] Failed to load NSS libraries.
Installing breakpad exception handler for appid(steamwebhelper)/version(20140922201705)
Installing breakpad exception handler for appid(steamwebhelper)/version(1411417025)
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number
Installing breakpad exception handler for appid(steam)/version(1411443970)
Installing breakpad exception handler for appid(steam)/version(1411443970)
Installing breakpad exception handler for appid(steam)/version(1411443970)
Installing breakpad exception handler for appid(steam)/version(1411443970)
Installing breakpad exception handler for appid(steam)/version(1411443970)
[0925/162904:ERROR:renderer_main.cc(227)] Running without renderer sandbox
[0925/162904:ERROR:renderer_main.cc(227)] Running without renderer sandbox
Generating new string page texture 12: 48x256, total string texture memory is 49.15 KB
Generating new string page texture 13: 256x256, total string texture memory is 311.30 KB
Generating new string page texture 14: 128x256, total string texture memory is 442.37 KB
Generating new string page texture 15: 384x256, total string texture memory is 835.58 KB
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number
Steam: An X Error occurred
X Error of failed request:  BadValue (integer parameter out of range for operation)
Major opcode of failed request:  18 (X_ChangeProperty)
Value in failed request:  0xffffffff
Serial number of failed request:  738
xerror_handler: X failed, continuing
Uploading dump (out-of-process) [proxy '']
/tmp/dumps/assert_20140925162903_1.dmp
/home/energy/.steam/steam.sh: line 729:  3598 Segmentation fault      $STEAM_DEBUGGER "$STEAMROOT/$STEAMEXEPATH" "$@"
Requested Force create but SharedObjectMutex already created
Forced create but already created for SharedObjectEvent
Forced create but already created for SharedObjectEvent
Finished uploading minidump (out-of-process): success = yes
response: CrashID=bp-e348f5b2-d334-4bf1-bc1d-0cb5a2140925

I have a Nvidia GeForce GT630M display card and the driver installed is version 331.38 .

System Info:

energy-acer               
    description: Notebook
    product: Aspire V3-571G (Type1Sku0)
    vendor: Acer
    version: V1.05
    serial: NXRZLCF0032140139F1601
    width: 64 bits
    capabilities: smbios-2.7 dmi-2.7 vsyscall32
    configuration: chassis=notebook family=Type1Family sku=Type1Sku0 uuid=35BEC001-6E6D-11E1-B972-DC0EA1A546F7
  *-core
       description: Motherboard
       product: VA50_HC_HR
       vendor: Acer
       physical id: 0
       version: Type2 - Board Version
       serial: NXRZLCF0032140139F1601
       slot: Type2 - Board Chassis Location
     *-firmware
          description: BIOS
          vendor: Acer
          physical id: 0
          version: V1.05
          date: 03/15/2012
          size: 128KiB
          capacity: 3520KiB
          capabilities: pci upgrade shadowing cdboot bootselect edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb biosbootspecification uefi
     *-memory
          description: System Memory
          physical id: 10
          slot: System board or motherboard
          size: 8GiB
        *-bank:0
             description: DIMM DDR3 Synchronous 666 MHz (1.5 ns)
             product: NT4GC64B8HD0NS-CG
             vendor: Nanya Technology
             physical id: 0
             serial: 0074117D
             slot: DIMM0
             size: 4GiB
             width: 64 bits
             clock: 666MHz (1.5ns)
        *-bank:1
             description: [empty]
             product: Empty
             vendor: Empty
             physical id: 1
             serial: Empty
             slot: DIMM1
        *-bank:2
             description: DIMM DDR3 Synchronous 666 MHz (1.5 ns)
             product: AD73I1C1674EV
             vendor: A-DATA Technology
             physical id: 2
             serial: 00004550
             slot: DIMM1
             size: 4GiB
             width: 64 bits
             clock: 666MHz (1.5ns)
        *-bank:3
             description: [empty]
             product: Empty
             vendor: Empty
             physical id: 3
             serial: Empty
             slot: DIMM3
     *-cpu
          description: CPU
          product: Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz
          vendor: Intel Corp.
          physical id: 21
          bus info: cpu@0
          version: Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz
          serial: To Be Filled By O.E.M.
          slot: U3E1
          size: 1200MHz
          capacity: 4GHz
          width: 64 bits
          clock: 100MHz
          capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid cpufreq
          configuration: cores=2 enabledcores=2 threads=4
        *-cache:0
             description: L1 cache
             physical id: 23
             slot: L1 Cache
             size: 32KiB
             capacity: 32KiB
             capabilities: internal write-through instruction
        *-cache:1
             description: L2 cache
             physical id: 24
             slot: L2 Cache
             size: 256KiB
             capacity: 256KiB
             capabilities: internal write-through unified
        *-cache:2
             description: L3 cache
             physical id: 25
             slot: L3 Cache
             size: 3MiB
             capacity: 3MiB
             capabilities: internal write-back unified
     *-cache
          description: L1 cache
          physical id: 22
          slot: L1 Cache
          size: 32KiB
          capacity: 32KiB
          capabilities: internal write-through data
     *-pci
          description: Host bridge
          product: 2nd Generation Core Processor Family DRAM Controller
          vendor: Intel Corporation
          physical id: 100
          bus info: pci@0000:00:00.0
          version: 09
          width: 32 bits
          clock: 33MHz
        *-pci:0
             description: PCI bridge
             product: Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port
             vendor: Intel Corporation
             physical id: 1
             bus info: pci@0000:00:01.0
             version: 09
             width: 32 bits
             clock: 33MHz
             capabilities: pci pm msi pciexpress normal_decode bus_master cap_list
             configuration: driver=pcieport
             resources: irq:40 ioport:2000(size=4096) memory:b2000000-b30fffff ioport:a0000000(size=301989888)
           *-generic UNCLAIMED
                description: Unassigned class
                product: Illegal Vendor ID
                vendor: Illegal Vendor ID
                physical id: 0
                bus info: pci@0000:01:00.0
                version: ff
                width: 32 bits
                clock: 66MHz
                capabilities: bus_master vga_palette cap_list
                configuration: latency=255 maxlatency=255 mingnt=255
                resources: memory:b2000000-b2ffffff memory:a0000000-afffffff memory:b0000000-b1ffffff ioport:2000(size=128) memory:b3000000-b307ffff
        *-display
             description: VGA compatible controller
             product: 2nd Generation Core Processor Family Integrated Graphics Controller
             vendor: Intel Corporation
             physical id: 2
             bus info: pci@0000:00:02.0
             version: 09
             width: 64 bits
             clock: 33MHz
             capabilities: msi pm vga_controller bus_master cap_list rom
             configuration: driver=i915 latency=0
             resources: irq:43 memory:b3400000-b37fffff memory:c0000000-cfffffff ioport:3000(size=64)
        *-usb:0
             description: USB controller
             product: 7 Series/C210 Series Chipset Family USB xHCI Host Controller
             vendor: Intel Corporation
             physical id: 14
             bus info: pci@0000:00:14.0
             version: 04
             width: 64 bits
             clock: 33MHz
             capabilities: pm msi xhci bus_master cap_list
             configuration: driver=xhci_hcd latency=0
             resources: irq:41 memory:b3a00000-b3a0ffff
        *-communication
             description: Communication controller
             product: 7 Series/C210 Series Chipset Family MEI Controller #1
             vendor: Intel Corporation
             physical id: 16
             bus info: pci@0000:00:16.0
             version: 04
             width: 64 bits
             clock: 33MHz
             capabilities: pm msi bus_master cap_list
             configuration: driver=mei_me latency=0
             resources: irq:44 memory:b3a14000-b3a1400f
        *-usb:1
             description: USB controller
             product: 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2
             vendor: Intel Corporation
             physical id: 1a
             bus info: pci@0000:00:1a.0
             version: 04
             width: 32 bits
             clock: 33MHz
             capabilities: pm debug ehci bus_master cap_list
             configuration: driver=ehci-pci latency=0
             resources: irq:16 memory:b3a19000-b3a193ff
        *-multimedia
             description: Audio device
             product: 7 Series/C210 Series Chipset Family High Definition Audio Controller
             vendor: Intel Corporation
             physical id: 1b
             bus info: pci@0000:00:1b.0
             version: 04
             width: 64 bits
             clock: 33MHz
             capabilities: pm msi pciexpress bus_master cap_list
             configuration: driver=snd_hda_intel latency=0
             resources: irq:45 memory:b3a10000-b3a13fff
        *-pci:1
             description: PCI bridge
             product: 7 Series/C210 Series Chipset Family PCI Express Root Port 1
             vendor: Intel Corporation
             physical id: 1c
             bus info: pci@0000:00:1c.0
             version: c4
             width: 32 bits
             clock: 33MHz
             capabilities: pci pciexpress msi pm normal_decode bus_master cap_list
             configuration: driver=pcieport
             resources: irq:17 memory:9fb00000-9fbfffff ioport:b3800000(size=1048576)
           *-network
                description: Ethernet interface
                product: NetLink BCM57785 Gigabit Ethernet PCIe
                vendor: Broadcom Corporation
                physical id: 0
                bus info: pci@0000:02:00.0
                logical name: eth2
                version: 10
                serial: dc:0e:a1:a5:46:f7
                capacity: 1Gbit/s
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi msix pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
                configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.134 firmware=sb latency=0 link=no multicast=yes port=twisted pair
                resources: irq:16 memory:b3830000-b383ffff memory:b3840000-b384ffff memory:b3850000-b38507ff
           *-generic:0
                description: SD Host controller
                product: BCM57765/57785 SDXC/MMC Card Reader
                vendor: Broadcom Corporation
                physical id: 0.1
                bus info: pci@0000:02:00.1
                version: 10
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list
                configuration: driver=sdhci-pci latency=0
                resources: irq:17 memory:b3800000-b380ffff
           *-generic:1 UNCLAIMED
                description: System peripheral
                product: BCM57765/57785 MS Card Reader
                vendor: Broadcom Corporation
                physical id: 0.2
                bus info: pci@0000:02:00.2
                version: 10
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list
                configuration: latency=0
                resources: memory:b3810000-b381ffff
           *-generic:2 UNCLAIMED
                description: System peripheral
                product: BCM57765/57785 xD-Picture Card Reader
                vendor: Broadcom Corporation
                physical id: 0.3
                bus info: pci@0000:02:00.3
                version: 10
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list
                configuration: latency=0
                resources: memory:b3820000-b382ffff
        *-pci:2
             description: PCI bridge
             product: 7 Series/C210 Series Chipset Family PCI Express Root Port 2
             vendor: Intel Corporation
             physical id: 1c.1
             bus info: pci@0000:00:1c.1
             version: c4
             width: 32 bits
             clock: 33MHz
             capabilities: pci pciexpress msi pm normal_decode bus_master cap_list
             configuration: driver=pcieport
             resources: irq:16 memory:b3900000-b39fffff ioport:9fc00000(size=1048576)
           *-network
                description: Wireless interface
                product: AR9462 Wireless Network Adapter
                vendor: Qualcomm Atheros
                physical id: 0
                bus info: pci@0000:03:00.0
                logical name: wlan0
                version: 01
                serial: 44:6d:57:15:2c:9a
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless
                configuration: broadcast=yes driver=ath9k driverversion=3.13.0-24-generic firmware=N/A ip=10.7.9.165 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
                resources: irq:17 memory:b3900000-b397ffff memory:9fc00000-9fc0ffff
        *-usb:2
             description: USB controller
             product: 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1
             vendor: Intel Corporation
             physical id: 1d
             bus info: pci@0000:00:1d.0
             version: 04
             width: 32 bits
             clock: 33MHz
             capabilities: pm debug ehci bus_master cap_list
             configuration: driver=ehci-pci latency=0
             resources: irq:23 memory:b3a18000-b3a183ff
        *-isa
             description: ISA bridge
             product: HM77 Express Chipset LPC Controller
             vendor: Intel Corporation
             physical id: 1f
             bus info: pci@0000:00:1f.0
             version: 04
             width: 32 bits
             clock: 33MHz
             capabilities: isa bus_master cap_list
             configuration: driver=lpc_ich latency=0
             resources: irq:0
        *-storage
             description: SATA controller
             product: 7 Series Chipset Family 6-port SATA Controller [AHCI mode]
             vendor: Intel Corporation
             physical id: 1f.2
             bus info: pci@0000:00:1f.2
             version: 04
             width: 32 bits
             clock: 66MHz
             capabilities: storage msi pm ahci_1.0 bus_master cap_list
             configuration: driver=ahci latency=0
             resources: irq:42 ioport:3088(size=8) ioport:3094(size=4) ioport:3080(size=8) ioport:3090(size=4) ioport:3060(size=32) memory:b3a17000-b3a177ff
        *-serial UNCLAIMED
             description: SMBus
             product: 7 Series/C210 Series Chipset Family SMBus Controller
             vendor: Intel Corporation
             physical id: 1f.3
             bus info: pci@0000:00:1f.3
             version: 04
             width: 64 bits
             clock: 33MHz
             configuration: latency=0
             resources: memory:b3a15000-b3a150ff ioport:3040(size=32)
     *-scsi:0
          physical id: 1
          logical name: scsi0
          capabilities: emulated
        *-disk
             description: ATA Disk
             product: WDC WD5000BPVT-2
             vendor: Western Digital
             physical id: 0.0.0
             bus info: scsi@0:0.0.0
             logical name: /dev/sda
             version: 01.0
             serial: WD-WX31CC1H7371
             size: 465GiB (500GB)
             capabilities: partitioned partitioned:dos
             configuration: ansiversion=5 sectorsize=4096 signature=7f5be2d2
           *-volume:0
                description: Windows NTFS volume
                physical id: 1
                bus info: scsi@0:0.0.0,1
                logical name: /dev/sda1
                version: 3.1
                serial: 5a08-aa96
                size: 16GiB
                capacity: 17GiB
                capabilities: primary ntfs initialized
                configuration: clustersize=4096 created=2012-04-02 16:31:41 filesystem=ntfs label=PQSERVICE state=clean
           *-volume:1
                description: Windows NTFS volume
                physical id: 2
                bus info: scsi@0:0.0.0,2
                logical name: /dev/sda2
                version: 3.1
                serial: bcecf70d-d5b1-604d-b7b0-c64e2d4b850a
                size: 98MiB
                capacity: 100MiB
                capabilities: primary bootable ntfs initialized
                configuration: clustersize=4096 created=2012-04-02 16:31:44 filesystem=ntfs label=SYSTEM RESERVED state=clean
           *-volume:2
                description: Windows NTFS volume
                physical id: 3
                bus info: scsi@0:0.0.0,3
                logical name: /dev/sda3
                version: 3.1
                serial: 8edda6ad-f704-5240-940d-913a9a8637b5
                size: 223GiB
                capacity: 223GiB
                capabilities: primary ntfs initialized
                configuration: clustersize=4096 created=2014-08-31 17:26:49 filesystem=ntfs label=Acer state=clean
           *-volume:3
                description: Extended partition
                physical id: 4
                bus info: scsi@0:0.0.0,4
                logical name: /dev/sda4
                size: 224GiB
                capacity: 224GiB
                capabilities: primary extended partitioned partitioned:extended
              *-logicalvolume:0
                   description: HPFS/NTFS partition
                   physical id: 5
                   logical name: /dev/sda5
                   capacity: 124GiB
              *-logicalvolume:1
                   description: Linux filesystem partition
                   physical id: 6
                   logical name: /dev/sda6
                   logical name: /
                   capacity: 93GiB
                   configuration: mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,data=ordered state=mounted
              *-logicalvolume:2
                   description: Linux swap / Solaris partition
                   physical id: 7
                   logical name: /dev/sda7
                   capacity: 7247MiB
                   capabilities: nofs
     *-scsi:1
          physical id: 2
          logical name: scsi2
          capabilities: emulated
        *-cdrom
             description: DVD-RAM writer
             product: DVD-RAM UJ8B0AW
             vendor: MATSHITA
             physical id: 0.0.0
             bus info: scsi@2:0.0.0
             logical name: /dev/cdrom
             logical name: /dev/sr0
             version: 1.00
             capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram
             configuration: ansiversion=5 status=nodisc