From last week We started using Office 2007 form 2003.

All of suddan this morning we started receiving error while opening the excel file

excel cannot open the file because the file format or file extension is not valid

Can any one help me on this

• Moved by Sally Tang Thursday, August 05, 2010 6:10 AM (From:Office IT Pro General Discussions)

Hi,

I would like to confirm if you have opened the Excel file in Excel 2007 before? Also, did this issue occur when you double click the Excel file, or try to open the Excel file in the Excel program?

If the problem occurs when trying to double click the Excel file, this issue is related to the file association. We can try the steps below to change the file association.

Step 1: Show File name extensions:

=======================

1. In Windows XP: Open “My Computer” or “Windows Explorer”. On the Tools menu, click Folder Options.

In Windows Vista or Windows 7, click the “Start” peal, in the “Search” box, type “Folder Options” and you can open “Folder Options“.

1. Click the “View” tab.
2. In the “Advanced settings” box, click to clear the “Hide extensions for known file types” check box.
3. Click OK.

Step 2: To change which program starts when you double-click a file

=============

1.       Right click the Excel file, and choose “Properties”.

2.       In the “General” tab, click the “Change” button. Here you will find a list of programs, choose the related Office program. If you don’t find it in the list, click the “browse” button and locate the application file on the disk.

3.       Click to select the “Always use the selected program to open this kind of file” check box if it is not selected.

4.       Click OK.

Check again if we can open the Office document by double clicking on it.

If the problem persists after this or the problem also occurs when trying to open the Excel file in the Excel program, let’s try to start Excel in safe mode, and then try to open the Excel files again.

==============

Click Start, point to All Programs, and then point to Microsoft Office.

Press and hold the CTRL key, and then click Microsoft Excel 2007.

Click the Office button > Open to open the Excel file.

Can we open it now?

Best Regards,

Sally Tang

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact tngfb@microsoft.com  

HI I have tyr both the option but no luck

any other suggestion

Hi

One more thing I have try opening the same file from my laptop but same Problem

they recently upgraded to 15 computer it dose not open form any of them.

even I try opening the file form office 2k3 with compatibility pack. But no luck

I cannot understand how this can happen all of sudden all of excel file

Thanks

Hi,

I am sorry to hear that the problem persists.

What’s the version and edition of your operating system?

Best Regards,

Sally Tang

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact tngfb@microsoft.com  

Hi,

I am writing to see how everything is going with this issue. Is the problem resolved? If there is anything I can do for you, please feel free to let me know.

Best Regards,

Sally Tang

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact tngfb@microsoft.com   

Hi,

As I have not heard from you for several days. I will go ahead and close this thread. If this issue is not resolved or you have any questions, please feel free to reply to us and this thread will be re-opened.

Best Regards,

Sally Tang

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact tngfb@microsoft.com   

Dear Sally

I tried to convert an SPSS data file to excel 2007 format by saving as .xlsx. But on opening the file (which is around 240mb in SPSS) I get the same error message as above. Now after I followed the steps you detailed (folder options etc), there is a hint of progress, but unfortunately as it is opening the file, MS excel fails to respond.

Shall be really grateful if you could help me out.

Many thanks

Abhimanyu 

if MS office is this type of extension problem then i think the children's will must learn Open Office, because some of my student lost his all excel files & now they in fear to save a excel file. His all file can not open & error is" ............file format or extension not valid........". Now what i suggest them............

This problem can be occured by CryptoLock Ransomware.

more information here:

http://www.geek.com/apps/disk-encryptiing-cryptolocker-malware-demands-300-to-decrypt-your-files-1570402/

you can also refer to this link to protect your pc from getting infected again.

http://social.technet.microsoft.com/Forums/office/en-US/f87ed2a8-cb45-4e13-b479-02268e80a384/ms-excle-encrypted?forum=excel

• Edited by TheHumanBot 5 minutes ago