Hello @leftmostcat, Steam's library UI has been overhauled since this issue report. If you come across this issue again with an up to date client, it will need a new investigation. Possibly was a rare server-sided issue.
Closing as outdated.
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
Library pane does not show categories. I had previously created a number of categories and used them for a period of years. After multiple client restarts on three different systems over a period of days (and client updates), categories are still absent.
Steps for reproducing this issue:
Unknown. Issue appeared with no immediately apparent cause.