Memo file is missing or invalid
Suddenly you get a "Memo file is missing or invalid" error message when you open a table. You close all open applications, run Visual FoxPro, open the table. and no error. All seems to be well, until a few weeks later you get the error again.
USE SYS(2005) AGAIN
if you clear the read-only flag, you can open the table without error, even in the second instance that failed to open the file a few seconds ago. The error only happens, when the file wasn't read-only when the first instance opened it.