excel cannot access the file there are several possible reasons

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Microsoft Office Excel cannot access the file ‘c:\file.xlsx’. There are several possible reasons:
• The file name or path does not exist.
• The file is being used by another program.
• The workbook you are trying to save has the same name as a currently open workbook.

Solution

As it’s stated here, follow these 2 easy steps. Then you can go back to your normal life!

1. Create directoryC:\Windows\SysWOW64\config\systemprofile\Desktop (for 64 bit Windows) or C:\Windows\System32\config\systemprofile\Desktop (for 32 bit Windows)
2. Set full control permissions on Desktop directory above (for example in Win7 > IIS 7 > DefaultAppPool: set permissions for user IIS AppPool\DefaultAppPool)