There are a few different things that could cause this.

• The PC Tablet service is running. You may need to manually stop the PC Tablet service.
• Your anti-virus software may be terminating the TwistedBrush. Adjust your anti-virus software to allow TwistedBrush or disable temporarily to test if that is the issue.
• Other software running on your system is incompatible with TwistedBrush. Start Windows in Safe Mode and test if TwistedBrush starts normally. If it does then it is likely other software is conflicting with TwistedBrush in a normal start.
• You may have some restriction on your computer (most usually in Windows 10). You can try to start the program as Administrator. This can be accomplished by clicking on the program icon with the right mouse button and selecting "Run as Administrator".
• The configuration of TwistedBrush may be faulty. Please remove the file TwistedBrush.env and start TwistedBrush.
• If still having an issue you can install TwistedBrush into a different directory.
• On a very small percentage of Windows Vista systems the auto switching from Aero to Vista Basic color themes doesn't work. This is purely a Windows function, TwistedBrush isn't doing or actually even requesting it but Windows determines it needs to be done based on the features of the OS that TwistedBrush uses. Manually switch from the Aero theme to the Vista Basic theme before starting TwistedBrush to see if that is the problem.