What operating system are you using?
Are you sure it's the v1.23 update? This build was released about 6 months ago.

Right click the game in Steam, and select "Video Settings Editor" or "Configuration Editor" or however it may be worded. Next follow the pictures:
http://wiki.gearcity.info/lib/exe/fetch.php?t=1497431976&w=480&h=500&tok=8dda8f&media=gamemanual:resetvideosettings.png

Do 1, and then 2, then close the settings editor, and relaunch the game.

THX for the fast respond
Version is v1.23.4, updated a few days ago, OS is Win 10 64bit
I have done what you told me, but I can´t click.
When I disable the Hardware Mouse in the engine settings I can see the Mouse-Arrow in the left upper corner, but I can´t move it. With Hardware Mouse enabled I can move the Mouse-Arrow around but unable to click

Originally posted by Box:

THX for the fast respond

Quite welcome, and thanks for the information.

Have you rebooted your computer? If not, try that first.

If it still doesn't work, email me the log file.
http://wiki.gearcity.info/doku.php?id=troubleshooting:steam_installfolder#getting_the_log_file

After I get the log, I may have you do a full clean reinstall. But we'll wait for that.

I deleted GearCity manualy after I switched to the stable Version 1.22, then I reinstalled with Steam to 1.22, Mouse worked, then I updated it via Steam to 1.23.4, and now Mouse work!
I think there was a Problem with the Steam Update.
THX again and Thumbs Up for this fantastic game :-))

Yeah, Steam breaks stuff with updates all the time. It's amazing how they manage to do that. :(

Glad you got it working! Enjoy! :)