Compression Error Can Lead to Partition Inaccessibility ? Data Recovery Tips

Almost everyone thinks of compressing partitions as it helps to save a considerable amount of disk space and increase the system performance. To perform a directory level compression of NTFS partitions, there is a ‘Compress’ option in its properties. You can also use ‘Compact.exe’ command-line utility for compressing multiple folders and files present on your NTFS partitions. However, when you try to compress a partition which has an allocation unit size of more than 4K bytes, it would lead to several compression errors. This may cause corruption of some of your data files or the whole partition may become inaccessible. To overcome this situation and recover all the partition data safely, you need to use a reliable third-party data recovery software.

For instance, you try compressing one of your NTFS partitions. You do not see the ‘Compress’ option in its properties. Furthermore, when you use ‘Compact.exe’ to compress the same partition, you may receive the following error message:

?The file system does not support compression?

The compression fails giving you information like 0 files within 1 directories have been compressed.


You are compressing a very large NTFS partition with a cluster size greater than the default value (i.e. 4096 bytes).

Allocation unit size, also known as cluster size, is a parameter that informs the device about the expected amount of disk space to allocate to a particular file. It helps in optimizing the buffer management. The default value is 4096 bytes for an NTFS partition. If you try to change this, you may encounter problems as above.


Try anyone of these steps to resolve the issue-

  • Run ‘Chkdsk’ utility to find out the allocation size of the partition.
  • Use Disk Administrator to reformat the NTFS partition. While reformatting, specify the allocation unit size as 4096 bytes.
  • Use a backup to perform data recovery.

In case of backup unavailability or failure of the above resolution steps, you should take help of an efficient data recovery software to recover all your precious data stored on the partition. These software can recover lost files, documents, emails, videos, databases etc. from your system in all cases of disk corruption and inaccessibility.



  1. This happened to me, & I had no idea how to solve it. luckily i had all of my data backed up and now am scared to try any sort of compression again. This article is very informative and might even give me the heart to try, when the time comes again. Are there any kind of compression tools for free that can help you avoid this problem? thanks again, Dave

  2. The big catch here being is that you kind of need the information backed up BEFORE compressing. There is also the small matter that an external HDD of over a terabyte goes at such a miniscule price, that it makes the risks of compressing unnecessary.

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