Excel general format changes to time/date format without notice

[WorriedNoodle]

I have some fairly large Excel spreadsheets, and I notice from time to time when I open them the cells that were formatted as general have changed to a useless date/time format. The fix is to select cells and choose general format again. This is time consuming.

* Anyone know why Excel does this? I'm using ver 2013, but had same issue with 2010.

[DogNo1]

Bug? You can reformat all of the cells in your workbook with a few clicks!

[WorriedNoodle]

Bug? You can reformat all of the cells in your workbook with a few clicks!

Yes I believe it is a bug Microsoft hasn't fixed for years, but cannot be sure. Like I said it is time consuming - not a few clicks. If I select the whole workbook and switch to general format cells, then cells which should be time format would be useless. So I need to select the cells manually and change back from Microsofts imposed date/time format I didn't choose, to general.

I understand the way around this is to avoid general format on workbooks and sheets, but that takes time as well, esp if importing data from others,.