Troubleshooting

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Computer is running slowly or opening programs on the hard disk has become slow. Cause: The volumes on your hard disk may have become excessively fragmented, possibly because you have recently created a large number of files or folders or have installed new software. Solution: Analyze and then defragment the volumes on your hard disk if necessary. For more information, see Best practices
The display and report do not agree. Cause: The Analysis and Defragmentation displays provide a general view of a volume's fragmentation. The displays show less detail than the Analysis and Defragmentation reports, so if you compare the results you might notice discrepancies. For precise, numerical figures, always use the reports. Solution: Use the Analysis and Defragmentation displays only for a general idea of the volume's fragmentation. Use the Analysis and Defragmentation reports for precise, numerical figures. For more information, see Analysis and defragmentation displays and reports
There appear to be unmovable files on volumes other than the system volumes and boot volumes. Cause: Paging files appear as unmovable files in Disk Defragmenter. On NTFS volumes the NTFS change journal also appears as an unmovable file. Solution: This is by design because paging files cannot be moved and therefore cannot be defragmented. For more information, see Why files are not moved to some regions of NTFS-formatted volumes
The defragmentation report on an NTFS volume shows small files with a large number of fragments. Cause: When a file is open for write access, NTFS attempts to preallocate additional space to help prevent fragmentation as the file grows. When you defragment a volume, Disk Defragmenter does not allow the extra space to be moved and consolidated while the file is open. The extra space is shown as additional fragments in the report. Solution: Close the file to release the additional fragments and reduce the size of the file. The Size on disk value (right-click the file and then click Properties) reports the size that you would obtain if you closed the file.

Computer is running slowly or opening programs on the hard disk has become slow.

Cause: The volumes on your hard disk may have become excessively fragmented, possibly because you have recently created a large number of files or folders or have installed new software.

Solution: Analyze and then defragment the volumes on your hard disk if necessary. For more information, see Best practices

The display and report do not agree.

Cause: The Analysis and Defragmentation displays provide a general view of a volume's fragmentation. The displays show less detail than the Analysis and Defragmentation reports, so if you compare the results you might notice discrepancies. For precise, numerical figures, always use the reports.

Solution: Use the Analysis and Defragmentation displays only for a general idea of the volume's fragmentation. Use the Analysis and Defragmentation reports for precise, numerical figures. For more information, see Analysis and defragmentation displays and reports

There appear to be unmovable files on volumes other than the system volumes and boot volumes.

Cause: Paging files appear as unmovable files in Disk Defragmenter. On NTFS volumes the NTFS change journal also appears as an unmovable file.

Solution: This is by design because paging files cannot be moved and therefore cannot be defragmented. For more information, see Why files are not moved to some regions of NTFS-formatted volumes

The defragmentation report on an NTFS volume shows small files with a large number of fragments.

Cause: When a file is open for write access, NTFS attempts to preallocate additional space to help prevent fragmentation as the file grows. When you defragment a volume, Disk Defragmenter does not allow the extra space to be moved and consolidated while the file is open. The extra space is shown as additional fragments in the report.

Solution: Close the file to release the additional fragments and reduce the size of the file. The Size on disk value (right-click the file and then click Properties) reports the size that you would obtain if you closed the file.

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