Steam webhelper crashing :
The mitigation at this time is to install Steam in a "new Win 7 64-bit bottle "to regain functionality.
Please make sure it is installed in a new bottle not a the existing Steam bottle.
Note, the games will have to be installed again.
However there is a way to move the games from one bottle to another without going through the reinstall process. Our QA staff pointed this out in the following forum post :
https://www.codeweavers.com/compatibility/crossover/forum/steam?msg=224277
Steam client exhibits black window :
The black window issue can be mitigated within the Steam settings > Interface > uncheck 'enable gpu accelerated rendering', after this it should prompt to restart steam.
Steam games that use to work won't launch :
This is Catalina/crossover 19.0.2 specific. If the game worked in 19.0.1 but not in 19.0.2, revert to 19.0.1. Here is the link :