Toon Boom Harmony Problems

I have been using TBH20 for a long time without any problems. However, I recently took a break from using TBH20, during which time I downloaded some new games, and then there was a bug when I used TBH20 again. The brush and stage will not be displayed properly, the brush will be faulted, and the stage will become tilted. I also tested TBH17 and TBH21, which had exactly the

same problem. I don’t know what went wrong.

Try deleting your preferences and layout folders and starting fresh.
Location for Windows:
C:\Users\[username]\AppData\Roaming\Toon Boom Animation\Toon Boom Harmony Premium\
On Windows, the AppData folder is hidden. To display it in Explorer, in the top menu, open the View pane and check the Hidden Items checkbox.

Also have you updated your GPU(video card) Drivers?