Worksheet loses data when hew user opens file

I'm having a problem when a new user on a different computer opens this workbook. I have no problem when opening, editing, saving and closing. When I reopen the file again all data is intact. If a new user on a different computer on the same network opens the file and clicks on enable content all times in column 'O' change to the current time. Typing a name in the station cell will activate the current time in column 'O' and deleting it will remove the time. Also if I try to delete sheets 2 and 3 which are unused the same thing happens, column 'O' changes to the current time. I have done a lot of searching but can't figure out why this is happening. All suggestions very much appreciated.