Developer Tab Insert button disabled in Excel 2007 and 2010?
What is it: Insert option under Developer tab is greyed out and not allowing you click?
How to enable Developer tab:
Once you unprotect the sheet, this gets enabled.
Step 1: Go to Review tab and click on Unprotect.
Step 2: Enter the same password you used to protect the sheet and click OK.
Step 3: Go back to Developer and check the Insert button, it should be enabled now.