You receive "RAM on this computer may be unstable" error message when you attempt to copy a drive in Windows XP or Windows 2000.

When performing a copy with Casper on a Windows XP or Windows 2000 system, you receive an error similar to the following:

A data integrity problem has been detected. The RAM on this computer may be unstable.
Casper performs memory (RAM) verification by computing a checksum of the data immediately after it has been read into memory from the source and then re-computing this checksum immediately before the data is written to the destination. If the checksums differ, a memory verification error is reported.

A memory verification failure is typically caused by one of the following:
  • An improperly seated or defective RAM module.
  • Overclocking.
  • Excessive heat.
  • A defective motherboard.
The first step in diagnosing a memory verification error is to run a complete memory diagnostic on the system. Memtest86 is a well known and respected memory tester. You can download it free from (click the Free Download link). Memtest86+ is a newer derivative available at

Sometimes memory verification errors are the result of paging I/O errors, which are disk errors specific to virtual memory management in Windows. If there are no errors detected with the RAM, you should check for errors and/or warnings logged in the Windows System event log for additional information.

Follow this procedure:
  1. Click Start
  2. Click Control Panel
  3. Double-click Administrative Tools
  4. Double-click on Event Viewer
  5. Under Event Viewer (Local), click the System tree and review the events there. Look for items related to Disk, NTFS, or controller problems.
If you see Disk errors or warnings, especially paging I/O warnings, you should perform a surface analysis via chkdsk on the system and paging drives. This will check for and mark out any bad areas on the disk(s).

Follow this general procedure:
  1. Open My Computer
  2. Right-click on the drive to scan and select Properties
  3. Click the Tools tab.
  4. In the Error-checking box, click Check Now.
  5. In Check disk options, check the Automatically fix file system errors and Scan for and attempt recovery of bad sectors check boxes.
  6. Click Start.
  7. Repeat for all volumes to be scanned (particularly any which host Windows system files and/or Windows paging files)
  • Windows XP
  • Windows 2000

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