I have at a number of times had the problem when I tried to access a form via MODIFY FORM ... command that I would get an error message that the memo file (SCT) is invalid. This in the past has caused me to revert to backups. But I have found a possbile solution. If you get this error message, then immediately issue a COMPILE FORM ... command. This seems to fix the corruption in the SCT file and now allows editing (MODIFY FORM ... ). I have not found an instance yet where I have lost any previous edits to the methods or properties.

I have not tested with previous versions as this might also work.