The C0000006 error and troubleshooting suggestions

This article introduces the meaning of a C0000006 error and how to troubleshoot it.

Original product version:   Visual FoxPro
Original KB number:   2704157


You have an application written in Visual FoxPro. The application may terminate and close after reporting the following error:

ExceptionCode: C0000006 (In-page I/O error).


A C0000006 error is a networking or network connectivity error. Specifically, a C0000006 error is an in page I/O error. This error occurs when an application loses its underlying network connectivity.


Since a C0000006 error indicates a networking problem, the best option is to obtain a network trace and analyze the results. This normally involves opening a case with our Windows Platforms Support group to help you obtain the trace and interpret the results.

While a C0000006 error indicates an underlying network problem, there are some suggestions you can try that might help prevent this error.

  • Disable opportunistic locking in Windows: Configuring opportunistic locking in Windows
  • Move the executable, the Visual FoxPro runtime files, and data files to the same machine.
  • Make sure the VFP9RENU.dll file is the same major build (9 for 9, 8 for 8, etc.) as VFP9R.dll and VFP9T.dll.
  • Mark the .EXE \ runtimes read only.
  • Disable the creation of the Foxuser files (FOXUSER.DBF\.FPT) via the CONFIG.FPW file with a RESOURCE=OFF line unless you specifically need the file. The Foxuser files are created automatically and are one more set of files to cause a possible network failure.
  • Make sure you are running Service Pack 2 version of VFP 9.0. You can download Service Pack 2 from here: Microsoft Visual FoxPro 9.0 Service Pack 2.0
  • To generate more ideas, leverage the VFP forum community: VFP forum community