For years I have performed the following steps when testing .DLL's

  1. Open the .DLL project being tested (e.g. dbCommonLRX.dll)
  2. Create a forms app with a button. and a reference to the .DLL
  3. --
  4. In the button click add enough code to test the .DLL
  5. Run the app. Examine results. Close the app
  6. --
  7. for arguments sake the .DLL had to be fixed
  8. switch to the .DLL project, make changes and rebuild
  9. Continue steps 5 - 8 until results are correct


Today I get errors(see below) at step 8 when building the .DLL. If I close the app I don't get errors.

Errors fron .DLL build:

Could not copy "obj\Release\dbCommonLRX.dll" to "bin\Release\dbCommonLRX.dll". Exceeded retry count of 10. Failed. dbCommonLRX

Unable to copy file "obj\Release\dbCommonLRX.dll" to "bin\Release\dbCommonLRX.dll". The process cannot access the file 'bin\Release\dbCommonLRX.dll' because it is being used by another process. dbCommonLRX

We were off Tuesday. On Monday the above worked.

I have restarted my PC to no avail. I am just at a loss why this started happening.