I created a series of workbooks to store records for my employer last year. In November I left that job but now the books are having problems. Twice I have had to come back to fix them: both times something had caused the macro links in a custom toolbar to stop functioning. Instead, when pressed the button would say it could not open the file where the macros were loaded. The macros themselves worked fine and, after re-linking the macros, the buttons worked fine. Then it happened again, a month later.

Does anyone know what could be causing this? I love my old boss and remain on good terms with her, and I promised her I'd continue to provide support for these workbooks, but I don't want to keep treking out to her office after work to fix them