Hi,

I've created a workbook and left certain cells unprotected for input porposes. The rest is locked and protected from selecting and changing.
I would like the entire workbook to be locked after a predetermined amount of time.

I thought about three solutions:
1. time lock the input cells. (not sure it's possible)
2. prevent access to the file using a specific time password protection.
3. protect the file with a password and adding a marco that changes it after a predetermined amount of time (not sure it's safe enough)

what should be the easiest and safest to carry out? and of course, how?
your help would be highly appreciated.

Shai.