Sakura, I agree, that start time is annoyingly large.
Please, run steam in terminal with "time steam" command, exit it as soon as menu appear and post here terminal output, so we can compare.
Here is my log with timestamps (launching steam in "small mode"):
https://gist.github.com/Self-Perfection/5077332
And System Information:
https://gist.github.com/Self-Perfection/5077310

IMHO, 10s to show list of games is way too much.

Steam:
real 0m22.048s (It feels slower)
user 0m10.953s
sys 0m4.208s

My WM:
real 0m6.070s
user 0m0.256s
sys 0m0.236s

Openoffice:
real 0m5.073s
user 0m3.376s
sys 0m0.508

A slight slowdown is added to Steam because it keeps asking for me to sudo (not happening) to install something that doesn't even exist in my distro (or possibly even any distro other than Ubuntu/Ubuntu-based distros.)

real 0m16.236s
user 0m7.076s
sys 0m4.242s

On a quad-core 3.3GHz CPU. With having Steam been run earlier in the same session.

Some of the time to load is Steam communicating with servers to get your games licenses, another chunk is an older codepath thats apparently being removed in the future (ie, support pre-steampipe games).

I have the same problem, it's slow at startup :
Dell Precision Core i7 Extrem Edition
RAM : 8GB
SSD 256 GB
Internet connection : 28 Mb/s
Linux Mint 14 (Nadia) 64-Bit

Running Steam on linuxmint 14 64-bit
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
unlinked 0 orphaned pipes
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
[0318/212350:WARNING:proxy_service.cc(646)] PAC support disabled because there is no system implementation
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Process 8451 created /sorcier-ValveIPCSharedObjects3
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Generating new string page texture 2: 48x256, total string texture memory is 49,15 KB
Generating new string page texture 3: 256x256, total string texture memory is 311,30 KB
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Installing breakpad exception handler for appid(steam)/version(1363321760_client)
Adding license for package 0
Adding license for package 7
Adding license for package 37
Adding license for package 16549
roaming config store loaded successfully - 946 bytes.
migrating temporary roaming config store
ExecCommandLine: "/home/sorcier/.local/share/Steam/ubuntu12_32/steam"
Generating new string page texture 69: 32x256, total string texture memory is 344,06 KB
Generating new string page texture 70: 128x256, total string texture memory is 475,14 KB
Generating new string page texture 71: 64x256, total string texture memory is 540,67 KB
Generating new string page texture 72: 8x256, total string texture memory is 548,86 KB
Generating new string page texture 76: 128x256, total string texture memory is 131,07 KB
System startup time: 47,79 seconds
Running Steam on linuxmint 14 64-bit
STEAM_RUNTIME has been set by the user to: /home/sorcier/.local/share/Steam/ubuntu12_32/steam-runtime
ExecCommandLine: "/home/sorcier/.steam/root/ubuntu12_32/steam steam://open/driverhelperready"
CAPIJobRequestUserStats - Server response failed 2
ExecSteamURL: "steam://open/driverhelperready"

Any update to this issue? I have the same problem.

Still painfully slow startup compared to Windows for me. Happens even with the Steam runtime disabled.

Still really slow. First asking on 2013. Valve used to worry about Linux systems. What happened then?

~16s cold start
~15s after cache warm up

i7-8700k @ 5GHz
32GB RAM
System/Steam are on NVME-SSD
Library is on Bcache partition, cache device is NVME-SSD
Internet: 400MBit, rtt store.steampowered.com: min/avg/max/mdev = 12.477/12.769/13.348/0.335 ms
Steam Library: 280 installed games

I'd say considering my specs, this is kind of ... shall we say ... sub-optimal?

System startup time: 16.11 seconds
System startup time: 15.00 seconds

First start after a system boot is really slow. What's most annoying is that there is no window indicating that Steam is about to start. It sometimes takes like about 10 seconds or more until the "Connecting..." window appears. When I quit Steam (quit, not minimize into tray) and start it again it opens almost immediately.
I wish there was at least a window that pops up right after the "steam" command was executed, saying something like "Preparing to launch Steam...".

would like to see more info given on start up about what's going on behind the hood. this startup speed cost me an abandon in dota2

@FrankieEnc You could start Steam from a terminal to see what's taking so long, but closing the terminal will also close Steam itself.

I have written me a shell script that tries to keep track on Steam at launch. It shows a message window which will disappear once Steam was started: https://gist.github.com/darealshinji/ddd95237e4006c7558758fd77c6bd80f

I've to add that since the inclusion of a web browser to do almost anything, the steam client comsumes a lot of resources, so i like to close it when not needed.
But that means waiting 15 seconds more to start a game from it, and this is about the same time my entire kde desktop comes up after the firmware initialization.
MEH!

I'm shocked this is still an issue.
Linux Mint 20.3 using the current store.steam Deb and having since auto updated.
Takes 25 secs before load from SSD, that's nuts.

Takes 30 seconds on Linux Mint 21 MATE
EDIT 2026: I have since moved to CachyOS and everything works perfectly

Also on Linux Mint 20.3 and having this issue. The only workaround I have found (from this Reddit comment) is to launch steam with STEAMOS=ANYTHING steam

This issue is still relevant!
I'm on a highend system and the startup time is terrible

STEAMOS=ANYTHING steam

I tried this after a fresh reboot, no difference :/

I have to admit that after I moved from HDD to SSD the startup time got a lost faster.

This issue is still relevant! I'm on a highend system and the startup time is terrible

STEAMOS=ANYTHING steam

I tried this after a fresh reboot, no difference :/

Same here, to get it to skip the prelaunch checks I had to export the variable before running steam.

export STEAMOS=ANYTHING
steam-native

Another way to get quicker startup is with the SteamOS mode:

steam -gamepadui

This issue is really old, but still a problem in Ubuntu 24.04. I have installed steam using the official .deb

Here is my console output when starting steam:

steam.sh[60447]: Running Steam on ubuntu 24.04 64-bit
steam.sh[60447]: STEAM_RUNTIME is enabled automatically
setup.sh[60564]: Steam runtime environment up-to-date!
steam.sh[60447]: Steam client's requirements are satisfied
[2024-07-24 10:26:18] Startup - updater built Jul 16 2024 23:21:18
[2024-07-24 10:26:18] Startup - Steam Client launched with: '/home/user/.local/share/Steam/ubuntu12_32/steam' '-srt-logger-opened'
07/24 10:26:18 minidumps folder is set to /tmp/dumps
07/24 10:26:18 Init: Installing breakpad exception handler for appid(steam)/version(1721173382)/tid(60633)
[2024-07-24 10:26:18] Loading cached metrics from disk (/home/user/.local/share/Steam/package/steam_client_metrics.bin)
[2024-07-24 10:26:18] Using the following download hosts for Public, Realm steamglobal
[2024-07-24 10:26:18] 1. https://client-update.akamai.steamstatic.com, /, Realm 'steamglobal', weight was 1000, source = 'update_hosts_cached.vdf'
[2024-07-24 10:26:18] 2. https://cdn.cloudflare.steamstatic.com, /client/, Realm 'steamglobal', weight was 1, source = 'update_hosts_cached.vdf'
[2024-07-24 10:26:18] 3. https://cdn.steamstatic.com, /client/, Realm 'steamglobal', weight was 1, source = 'baked in'
[2024-07-24 10:26:18] Verifying installation...
[2024-07-24 10:26:18] Verification complete
UpdateUI: skip show logo
Steam logging initialized: directory: /home/user/.local/share/Steam/logs

XRRGetOutputInfo Workaround: initialized with override: 0 real: 0xe7993860
XRRGetCrtcInfo Workaround: initialized with override: 0 real: 0xe7991fc0
/usr/share/themes/Yaru-blue-dark/gtk-2.0/main.rc:775: error: unexpected identifier 'direction', expected character '}'
/usr/share/themes/Yaru-blue-dark/gtk-2.0/hacks.rc:28: error: invalid string constant "normal_entry", expected valid string constant
CAppInfoCacheReadFromDiskThread took 61 milliseconds to initialize
Steam Runtime Launch Service: starting steam-runtime-launcher-service
Steam Runtime Launch Service: steam-runtime-launcher-service is running pid 60754
bus_name=com.steampowered.PressureVessel.LaunchAlongsideSteam
BRefreshApplicationsInLibrary 1: 0ms
src/steamUI/webuitransportcontroller.cpp (206) : Failed to connect to websocket
src/steamUI/webuitransportcontroller.cpp (206) : Failed to connect to websocket
07/24 10:27:03 Init: Installing breakpad exception handler for appid(steam)/version(1721173382)/tid(60633)
assert_20240724102703_36.dmp[61589]: Uploading dump (out-of-process)
/tmp/dumps/assert_20240724102703_36.dmp
BuildCompleteAppOverviewChange: 236 apps
RegisterForAppOverview 1: 8ms
RegisterForAppOverview 2: 8ms
assert_20240724102703_36.dmp[61589]: Finished uploading minidump (out-of-process): success = yes
assert_20240724102703_36.dmp[61589]: response: CrashID=bp-c8bfd9f4-938e-4996-b10b-6909b2240724
assert_20240724102703_36.dmp[61589]: file ''/tmp/dumps/assert_20240724102703_36.dmp'', upload yes: ''CrashID=bp-c8bfd9f4-938e-4996-b10b-6909b2240724''

It seems to be taking it's time after BRefreshApplicationsInLibrary 1: 0ms, followed by src/steamUI/webuitransportcontroller.cpp (206) : Failed to connect to websocket

Still an issue on Ubuntu 24.04, snap package.

When I have not opened the steam app for some time, and it has a lot of updates to install, it can take several minutes to startup but it does not show any splash screen, system-tray icon, or other indication that it is running.

This is a problem because it made me think that the launcher had crashed or frozen before I figured out what was going on.
Launching from the terminal reveals that it is just running updates.

I will try to time it in the future, but I'll need to wait for some updates to accumulate first to get an accurate read.

Timed the startup, trimmed output for readability...

> time steam
Testing for explicit PulseAudio choice...
...and PulseAudio has been explicitly chosen, so using it.
INFO: filtering /usr/share/ubuntu out of XDG_DATA_DIRS because it is unreachable
INFO: filtering /usr/share/gnome out of XDG_DATA_DIRS because it is unreachable
INFO: filtering /etc/xdg/xdg-ubuntu out of XDG_CONFIG_DIRS because it is unreachable
steam.sh[20925]: Running Steam on ubuntu 24.04 64-bit
steam.sh[20925]: STEAM_RUNTIME is enabled automatically
setup.sh[20977]: Steam runtime environment up-to-date!
...
[2025-12-23 13:41:21] Manifest download: send request
[2025-12-23 13:41:21] Add pending download: https://client-update.fastly.steamstatic.com/steam_ubuntu12.zip.vz.5414ff13abbfd858c2731d7f9608de9a030dfce9_3329121
[2025-12-23 13:41:21] Manifest download: send request
[2025-12-23 13:41:21] Downloading update (139 of 107303 KB)...
[2025-12-23 13:41:21] Set status message: Downloading update (139 of 107303 KB)...
[----] Downloading update (139 of 107303 KB)...
[2025-12-23 13:41:21] Set percent complete: 0
[2025-12-23 13:41:21] Downloading update (603 of 107303 KB)...
[2025-12-23 13:41:21] Set status message: Downloading update (603 of 107303 KB)...
[  0%] Downloading update (603 of 107303 KB)...
[2025-12-23 13:41:21] Set percent complete: 0
...
[2025-12-23 13:42:32] Downloading update (107026 of 107303 KB)...
[2025-12-23 13:42:32] Set status message: Downloading update (107026 of 107303 KB)...
[ 99%] Downloading update (107026 of 107303 KB)...
[2025-12-23 13:42:32] Set percent complete: 99
[2025-12-23 13:42:32] Downloading update (107303 of 107303 KB)...
[2025-12-23 13:42:32] Download complete.
[2025-12-23 13:42:32] Set percent complete: -1
[2025-12-23 13:42:32] Set status message: Installing update...
[----] Installing update...
[2025-12-23 13:42:33] Extracting package...
[2025-12-23 13:42:33] Set status message: Extracting package...
[----] Extracting package...
[----] Extracting package...
[----] Extracting package...
...
[2025-12-23 13:42:37] Installing update...
[2025-12-23 13:42:37] Set status message: Installing update...
[----] Installing update...
[----] Installing update...
[----] Installing update...
...
[2025-12-23 13:42:38] Cleaning up...
[----] Installing update...
[----] Installing update...
[----] Installing update...
[2025-12-23 13:42:38] Update complete, launching Steam...
UpdateUI: skip show logo
[2025-12-23 13:42:38] Shutdown
[----] Installing update...
[----] Installing update...
...
[2025-12-23 13:42:38] ProcessNextMessage: socket disconnected
[2025-12-23 13:42:38] No more messages are expected - exiting
SaveRegistryVDF
SaveRegistryVDF completed successfully
steam.sh[20925]: Restarting Steam by request...
steam.sh[20925]: Running Steam on ubuntu 24.04 64-bit
setup.sh[21275]: Steam runtime environment up-to-date!
steam.sh[20925]: Log already open
steam.sh[20925]: Steam client's requirements are satisfied
...
Steam Runtime Launch Service: starting steam-runtime-launcher-service
Steam Runtime Launch Service: steam-runtime-launcher-service is running pid 21483
bus_name=com.steampowered.PressureVessel.LaunchAlongsideSteam
SaveRegistryVDF
SaveRegistryVDF completed successfully
SaveRegistryVDF
SaveRegistryVDF completed successfully
SaveRegistryVDF
SaveRegistryVDF completed successfully
Desktop state changed: desktop: { pos:    0,   0 size: 1920,1200 } primary: { pos:    0,   0 size: 1920,1200 }
Caching cursor image for default, size 24x24, serial 29, cache size = 0
SaveRegistryVDF
SaveRegistryVDF completed successfully
SaveRegistryVDF
SaveRegistryVDF completed successfully
sh: 1: lsb_release: not found
reaping pid: 21320 -- sh

At this point, the splash screen popped up, and the UI loaded

Then I closed the client and it shut down and gave me the time

...
[2025-12-23 13:43:36] Shutdown
SaveRegistryVDF
SaveRegistryVDF completed successfully

real	2m16.238s
user	0m20.800s
sys	0m1.990s

It took a little under 2 minutes to actually show the splash screen, since I launched in the terminal I could see the download, extract and install process, but launching from the desktop it seems like nothing hapenes, unless you ps aux | grep steam and note that the process is running.