Today we are looking at an old error that I've been meaning to post:
The file "...\TestDB.mdf" is compressed but does not reside in a read-only database or filegroup. The file must be decompressed.
This error popped up when I attempted to bring a DB online via the following command:
USE [master]
GO
ALTER DATABASE TestDB SET ONLINE
GO
As the error message indicates, there seems to be some kinda file compression going on somewhere. This compression could either be on the folders where the MDF and LDF files for the database reside or, the compression could be on the files themselves.
Thankfully, checking the folders and files for compression and then turning compression off, is the same.
- Right-click the folder containing the MDF/LDF files or right-click the files themselves.
- Choose 'Properties'. (Fig. 1)
- Choose 'Advanced...'.
- Uncheck "Compress contents to save disk space".
- Click 'Ok'.
- Click 'Apply' and 'Ok'.
 |
| Fig. 1: Smash that Advanced button |
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| Fig. 2: Remove the compression |
Repeat the above for any folders or files related to the database. Note: If a folder is compressed, the folder name will be in blue font. If a file is compressed, the file icon will be slightly different.
Hopefully that should end your woes. :-)
DISCLAIMER: As stated, I’m not an expert so please, PLEASE feel free to politely correct or comment as you see fit. Your feedback is always welcomed. :-)
