How to fix Photoshop's 'could not complete your request because of a program error' problem
Corrupted program files The error can occur on any Mac but seems to happen more often on a Mac that runs macOS Catalina or macOS Big Sur. This problem is also not unique to macOS, either — as it turns out, Windows users are suffering too. For both Windows and macOS users, the error often occurs when users attempt to create a new file or open an existing one. However, some users note that it has happened when performing certain functions in Photoshop, such as merging layers or applying filters, as well. The problem is so common, in fact, that many people have learned to live with it, assum...
Source: appleinsider.com