Troubleshooter

Kenneth, Alex's Troubleshooter is a good starting point. Back up the database before testing changes.

Since this started when you added the controls, check the form's Record Source in Design View. If it's a query, open that query directly and make sure both new fields are included and it runs without errors or unexpected parameter prompts. Then check that each new control's Control Source matches the intended field.

On a COPY of the form, remove just the two new controls, save and close it, then reopen it directly in Form View. Leave the table fields and their data alone. That will help narrow down whether adding those controls triggers the problem.

When you say it won't open, do you get an error message, a blank form, or no form window at all? Please post the exact error text, if any. Also let us know whether the form has an On Open or On Load macro/event procedure. The Layout View workaround is a useful clue, but it isn't enough to identify the cause yet.