Windows Service ran by domain account cannot access file while full control

Question

I have created a C# service that:

- Picks up and opens a local text file
- Opens an Excel-file used as template (saved locally)
- Fills in the data from the text file in the excel file
- Saves the Excel file to a network folder.

The service runs using a domain account (I cannot give the local system account rights on the network from our network admin...). When the service tries to open the template, I get an access denied error:

Microsoft Excel cannot access the file 'C:\BloxVacation\Template\BloxTemplate.xlsm'. 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.

The file does exist and the path is correct. The file is not used by another user or program. I try to OPEN the workbook (no other workbook is open), not SAVE it.

I have received the same error using the system account. The reason for this is that, when using interopservices, the system account needs a desktop folder (bug in Windows 7: http://forums.asp.net/t/1585488.aspx).

C:\Windows\System32\config\systemprofile\Desktop
C:\Windows\SysWOW64\config\systemprofile\Desktop

Create those 2 files and the error disappears for the system account.

I have given the domain user rights to those folders and the error disappears as well however, the service hangs on the code line where I open the excel file. When I execute the exact same code with the system account, the code execute well (Note: I save the file locally).

 objXL.Workbooks.Open(BloxVacationService.ExcelTemplateFilePath)

Has anybody an idea how to solve this issue without having to rewrite the entire service in OpenXML? Thank you very much in advance.

Answer 1

If you have done all the things described in the question and it still doesn't work (as it was with me), the answer is pretty simple:

Make the domain user local admin on the machine that runs the service. It solved the problem.