1884: Non-Removable 7.8 MB Of Unallocated Space On Hard Drive

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Last update: 14-11-2013

Explanation of why there can be up to 7.8 MBytes of unallocated space that cannot be removed by usual means


There are two situations in which partitioning software (e.g. Acronis Disk Director Server 10.0, Acronis Disk Director Suite 10.0, Acronis Disk Director Lite) can detect an area of unallocated space of up to 7.8 MB in size that was not created there manually:

  1. Up to 7.8 MB (minimum of 1MB) of unallocated space resides at the end of the hard disk. This area is reserved by Windows operating systems for the purpose of creation of Dynamic Disk structures. This unallocated space area is not shown in Windows Disk Management; however Acronis Disk Director is able to merge it with an adjacent partition. Therefore, after doing that there can be problems with creating Dynamic Disk structures.
  2. Exactly 7.8 MB of unallocated space reside at the beginning of the hard disk. Normally this means that there are no Primary partitions on the hard drive and the hard drive contains an Extended partition only. In such cases Windows reserves the minimal amount needed for creating a partition (7.8 MB) in order to be able to handle the only Extended partition properly. It is not recommended to remove this area. Even though technically it is possible to merge it with the Extended partition, this may result in the data on it becoming inaccessible.

More information

It is not recommended to remove the 7.8 MB space area.