When trying to edit an Excel-based form using the Edit Document button, you receive an error message saying that there was an error changing the editing mode. The error message may appear as:
- Unprotect method of worksheet class failed, or
- Exception from HRESULT: 0x800A03EC
If you are using the old TurboLaw Edit Document button (found on the Add-Ins tab in newer versions of Excel), you may not receive any error, but the document will not be unprotected and you won't be able to edit what you were trying to change.
This problem is caused by having the Shared Workbook feature turned on. In most cases, you can tell that this feature is turned on because the title bar of Excel will have the text "[Shared]" immediately following the name of the document.
This is a seldom-used feature of Microsoft Excel which allows multiple people to edit the same Excel file at the same time. However, when this option is enabled, certain features of Excel are not allowed - including unprotecting a cell (which is what the Edit Document button does).
To resolve this problem, disable the Shared Workbook feature.
In Excel 2003 and earlier:
- Click on Tools > Share Workbook and un-check the Allow Changes check box.
- You will receive a message asking whether you are sure you want to unshared the document. Click Yes.
In Excel 2007 or later:
- Click on the Review tab and then click on the Share Workbook button. Un-check the Allow Changes check box.
- If you are unable to un-check the Allow Changes check box, then you will have to unprotect the sheet - on the Review tab click the Unprotect Shared Workbook button.