Excel changes all my formats to time

Excel changes all my formats to time. This is the 3rd time it has happened in 2 weeks. any thoughts on how to fix this??

 

What Excel version? What Excel file type: xls, xlsx, or a different file type?

And what exactly do you mean by "changes formats"; perhaps you can provide some screenshots?

 

Thanks Pwillener,
Excel Version: Microsoft Excel 2010
FILE TYPE: XLSM

When this happens it changes ever cell in the entire large 17 tab worksheet to this time format. It happens after I save it and then when I open it the following morning it has all changed. Thanks for your help!!!

 

Greetings, lisa1977...

Pardon the intrusion: didn't know when pwillener would be logging back in...

This appears to be a fairly common Excel bug, especially when handling large spreadsheets (10-20 tabs and/or >15mb) or spreadsheets involving Pivot Tables. One thing you might check is if there are any custom formats loaded - if so, try deleting them and see if Excel will revert to and maintain the General ("Normal") format.

 

Excel files with the file extension .XLSM are macro enabled files, and it has to be a macro that is causing this change of cell format. Normal spreadsheets, i.e. those not macro enabled, have the file extension .XLS. Correct the cell format manually and save your file as .XLS

 

EDIT - as this is Excel 2010 the standard file format is .XLSX, not .XLS, though I'm pretty sure either will work.

 

Thanks Caliban,
How do I check for custom (preset) formats?? To the best of my knowledge, they are custom in regards to the fact that I formatted them. The file size is 1.62 MB

 

Thanks Earthing,
I have several macros I use in this Spreadsheet and that is why I use the xlsx format. I will revisit them and see if there is a bug in them that is creating this problem!

 

Click the 'Format' button, and in the corresponding menu see if there are any entries that you do not recognize or that you know you did not load - remove any oddities that you find.

Do the same in the Office folder(s): in Windows Explorer navigate to Program Files > Microsoft Office > Office12 (I don't have an XP machine available ATM, but your path should be similar) - look for any files that seem suspicious or out of whack. I wouldn't start randomly deleting anything in that folder, but you should be able to see if something's amiss.

 

Just correcting the format and saving and reloading as .XLSX will prove whether or not this problem is related to one of your macros. Process of elimination.

 

My turn to apologise for intruding - I do have same problem, apart from the sheet re-opens with most cells as currency.
I run W7, Excel 2010, file format is .xlsx which should be macros disabled, right?
It's a super-simple sheet, basically multiplying units with unit prices.
12 lines, total size of sheet 133kb.
See print attached - where it now shows ####### format when saved/closed was either NUMBER or GENERAL, but changes into CURRENCY.

Thanks in advance!