This happened on Windows 10 clicking on *.mws documents while Maple 2023 was not running.
My observations with one document (I do not have others at hand at the moment):
No freeze when Maple is already running.
No freeze when the startup page (Start.mw) is disabled.
Older versions opened in Windows file explorer with “right click and open with” did not show this behavior.
Since there are ways to open such old documents, my intention is to document my observations and to find out if others can reproduce it. If not, my setup might differ from default or the file has an issue.