Hi,
Try to reproduce this issue on a test environment without extension if applicable. if you still have the same issue reinstall web server components.
Additionally, there are three hotfixes available that fixed some clients crash issues:
CU 14 - The client crashes or the ribbon hangs.
CU18 - The Web client crashes when you try to filter on the Vendor No. field while opening a new purchase quote.
CU 22 - Crashes occur in the Client Designer when trying to save an extension that is using a field with ObsoleteState=Removed.