Could you share a screenshot of the popup please?

File In Use

Sorry about the double upload. Alex.  This is the screen shot when I double clicked the Form in the navigation area.

Try doing a Global search of your code. In the VB Editor click on the binoculars on the Toolbar (Ctrl+F), select Current Project and search for MsgBox. Keep clicking Find Next until you find the code that display the message.

Have you added any MsgBox?

A quick search says it's a "Fatal Exception Error" where the program has (at least partially) crashed. May happen when the program tries to access an invalid area of memory.

Primary causes

    Corrupted application files: The Access program or a file it uses has become corrupted. This is a common cause, especially in older versions.
    Insufficient resources: Your computer has run out of memory or other system resources needed to run the application properly.
    Third-party application conflict: Another program running on your computer is interfering with Access by requesting system resources it needs.
    Conflicting or damaged add-ins: An add-in or extension to Access is causing an invalid memory operation

Overall, the recommendations it gives are pretty much all covered in Troubleshooter.

Alex - No. I did add a combobox and a text box all connected to the OrderT.  Corrupted not shown on Compact and Repair or when code is compiled.   Donald - Resources not a problem, work was done on my new computer 32 gig ram and 1tb SDD high speed processor. No third-party applications running. No Add ins to MS Access. And it was working fine. I also have not had the DB opened since the last time I opened it to enter a new customer. Kevin= WOW! Found it in the code that came with the DB that I downloaded. I don't know why it was there. And I don't know why it did not show up before this. THAKS FOR ALL THE INPUT GUYS it is working normal now.

John So, are you saying it was a msgbox in the code?

Yes, it was the msgbox code, very strange, I did not even look at the code so I don't believe I did anything to cause this but who knows.