Disabling Excel File 30 Days After Download

[dunk123]

So I wish to post a zipped excel file on the web and have it expire after a certain amount of time (30 days say). This is easy enough by having code running OnOpen in the ThisWorkbook module.

However, what if I want to reliably have this file expire 30 days after the person has downloaded the file? I'm trying to avoid having to replace the file on the web all the time with a new fixed expiry date in the code.

Bear in mind it will be in a compressed folder too. Any thoughts?

Thanks all

 

[Warship]

Have a look at:
http://www.cpearson.com/Excel/workbooktimebomb.aspx

 

[MrKowz]

One possibility would be to create a password-locked worksheet (and password protect the vba code) that can store one value - the first date the file was opened, then you can test based off of that date with something like:

Private Sub workbook_open()
With Sheets("Cfg").Range("A1")
    If .Value = vbNullString Then
        .Value = Date
    ElseIf .Value + 30 >= Date Then
        MsgBox "Your evaluation period has ended."
        ActiveWorkbook.Close
    End If
End With
End Sub

However, this has several fallacies:

1. If VBA is disabled, this code will not run
2. If the person creates a copy of the file before running it the first time, they will be able to work around this code
3. Excel's security is not very secure. Even password protected workbooks/code can be cracked in seconds.

 

[dunk123]

Awesome, thanks guys. I'll check this stuff out.