DOCUMENT:Q264867  01-AUG-2000  [foxpro]
TITLE   :INFO: Possible Causes of Data Corruption in Visual FoxPro
PRODUCT :Microsoft FoxPro
PROD/VER:WINDOWS:3.0,3.0b,5.0,5.0a,6.0
OPER/SYS:
KEYWORDS:kbDatabase kbvfp300 kbvfp300b kbvfp500 kbvfp500a kbvfp600 KbDBFDBC kbGrpDSFox kbDSuppor

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The information in this article applies to:

 - Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a, 6.0 
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SUMMARY
=======

This article lists the possible causes of data corruption in Visual FoxPro. The
article also includes some tools for fixing data corruption.

MORE INFORMATION
================

Although this is by no means a complete list of every possible cause of
corruption, it is meant to be a starting point for troubleshooting data
corruption problems in Visual FoxPro.

Possible causes for data corruption are:

 - Abnormal termination of the application while manipulating data. This would
   include loss of power, voltage spikes, internal consistency errors, page
   faults, and fatal exception errors.

 - Substandard or faulty network components: Because FoxPro handles data so
   quickly, it can stress the network. These components may include network
   drivers, network interface cards, cabling, hubs, and switches.

 - Data storage components: Storage devices should be checked regularly for
   errors and fragmentation.

 - File locking issues: If one user performs an action that results in a table's
   memo file being locked, and a second user attempts to open the same table and
   access the memo field information, the second user may open the memo file
   with an incorrect blocksize, resulting in memo file corruption. See the
   "References" section in this article for details.

 - Conflicting software: Software such as Antivirus packages, screen savers, and
   terminate-and-stay-resident applications (TSRs) can cause conflicts with
   Visual FoxPro that could cause data corruption.

 - Incompatible video drivers: Certain video drivers can cause FoxPro to become
   unstable and terminate abnormally. See the "References" section in this
   article for more details.

 - Network Settings and Service Packs: Make sure that your servers are running
   the latest service packs, check client settings (such as caching), and even
   try switching network client drivers (such as from the Novell Netware client
   to the Microsoft client for Netware).


REFERENCES
==========

For additional information on the causes of corruption, click the article
numbers below to view the articles in the Microsoft Knowledge Base:

   Q99557 PRB: FoxPro Corruption Problems Fixed by Novell 3.11 Patches

   Q195405 FIX: Corrupt Record Added in Grid Using View with Default Value

   Q95232 PRB: Video Card Causes GP Faults or Display Problems

   Q195623 FIX: Index Corruption When Table is Used in Read-Only Mode

   Q164385 BUG: Large Result Sets May Become Corrupted in VFP

For additional information on specific methods for fixing corruption, click the
article numbers below to view the articles in the Microsoft Knowledge Base:

   Q193952 HOWTO: Troubleshoot to Resolve Suspected Corruption

   Q168762 HOWTO: Fix Index Corruption at Run Time with Visual FoxPro

   Q189458 INFO: Third Party Utility Repairs FoxPro Record and Memo Data


Additional query words:

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Keywords          : kbDatabase kbvfp300 kbvfp300b kbvfp500 kbvfp500a kbvfp600 KbDBFDBC kbGrpDSFox kbDSupport 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP500 kbVFP600 kbVFP500a
Version           : WINDOWS:3.0,3.0b,5.0,5.0a,6.0
Issue type        : kbinfo

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