DMax autonumber & duplicate problems

[teiben]

creating a db, not using the autonumber and instead using a txtbox w/
=DMax("[Requestnumber]","tblname")+1, which works great!
now I need to duplicate a record, using the wizard this works great too, but now I have two of the same requestnumbers.

Searched around forum and didn't locate an applicable soluation.... does anyone have a workaround..?

 

[AccessBlaster]

Have you tried to set a index on your requestnumbers to, Yes (No Duplicates)?

 

[teiben]

no such selection