Problem

User opens an xls file in excel 2010 and the following error appears

"cannot open file because the file format or file extension is not valid."

Fix

We managed to solve this issue in our domain by relaxing the group policy setting for Force file extension to match file type

This can be accessed via User configuration\Administrative templates\Microsoft Excel 2010)\Excel options\Security

The options are listed below

• Allow different
• Allow different but warn
• Always match file type

We set this to Allow different which then allowed the user to open the .XLS file in excel 2010

If you disable or do not configure this policy setting, if users attempt to open files with the wrong extension, Excel opens the file and displays a warning that the file type is not what Excel expected.

Thanks to share the helpful solution to us. This will help the others who meet the same issue.

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Problem

User opens an xls file in excel 2010 and the following error appears

"cannot open file because the file format or file extension is not valid."

Fix

We managed to solve this issue in our domain by relaxing the group policy setting for Force file extension to match file type

This can be accessed via User configuration\Administrative templates\Microsoft Excel 2010)\Excel options\Security

The options are listed below

• Allow different
• Allow different but warn
• Always match file type

We set this to Allow different which then allowed the user to open the .XLS file in excel 2010

If you disable or do not configure this policy setting, if users attempt to open files with the wrong extension, Excel opens the file and displays a warning that the file type is not what Excel expected.

i am not finding that gpo path.  user configuration next has to be either policies or preferences.  which is it?  and where from there.  could you check it and let me know where it is.  thanks

Problem

User opens an xls file in excel 2010 and the following error appears

"cannot open file because the file format or file extension is not valid."

Fix

We managed to solve this issue in our domain by relaxing the group policy setting for Force file extension to match file type

This can be accessed via User configuration\Administrative templates\Microsoft Excel 2010)\Excel options\Security

The options are listed below

• Allow different
• Allow different but warn
• Always match file type

We set this to Allow different which then allowed the user to open the .XLS file in excel 2010

If you disable or do not configure this policy setting, if users attempt to open files with the wrong extension, Excel opens the file and displays a warning that the file type is not what Excel expected.

i am not finding that gpo path.  user configuration next has to be either policies or preferences.  which is it?  and where from there.  could you check it and let me know where it is.  thanks