ScanDisk Fails Repairing Bad Allocated Cluster

• Microsoft Windows 95

SYMPTOMS

ScanDisk for Windows (SCANDSKW.EXE) may fail to repair a bad cluster that is in use (allocated to a file), and you may receive the following error message:

   ScanDisk was attempting to correct an error, but encountered
   another error while writing to one of the drive's data area
   sectors.

   ScanDisk can repair this error and detect other damaged sectors
   on the disk if you choose to perform a thorough test now. However,
   the data stored in this and any other damaged sectors may already
   be lost.

CAUSE

This error can occur if ScanDisk tries to write the data it could read from a bad cluster to a free cluster that is also bad (but has not yet been tested by ScanDisk).

RESOLUTION

To resolve this situation, follow these steps:

1. Run ScanDisk again and choose the Thorough option. Ignore any bad clusters that have files associated with them. Repair any bad clusters with no files associated with them.

2. Run ScanDisk again and choose the Thorough option. Repair any bad clusters with associated files.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows 95. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

On uncompressed drives, ScanDisk tries to repair bad clusters that are allocated to files by writing any data that can be read from the bad cluster to a free cluster, then repairing the cluster chain and marking the cluster as bad in the FAT.

When ScanDisk tries to write the data to a cluster that is also bad, ScanDisk should try to find another free cluster to write the data to. ScanDisk should fail only if it can find no other free clusters to write the data to. Instead, ScanDisk fails to repair the bad cluster and generates the error message stated above.