Error "Bootmgr is compressed": How to Fix the Issue

The "Bootmgr is compressed" error is a common problem faced by Windows users. This error appears at startup, preventing the computer from booting normally. It typically occurs when the operating system's boot manager file has been accidentally compressed, making it inaccessible to the system.

In this article, we will explore the causes of this error and provide quick and effective solutions.

Causes of the "Bootmgr is compressed" Error

The main reason for this error is the compression of the Bootmgr file, which is essential for loading the operating system. Here are some common causes:

  • Accidental Disk Compression. Sometimes, users enable disk compression to save space, inadvertently compressing the Bootmgr file in the process.
  • Disk Optimization Software. Certain optimization programs might compress critical system files, including Bootmgr.
  • File System Errors. System errors or failures can sometimes lead to the compression of files needed for Windows to boot.

How to Fix the "Bootmgr is compressed" Error

Here are some methods to restore normal system startup.

1. Using a Windows Installation Disk

The most reliable way to resolve this error is to use a Windows installation disk. Follow these steps:

  1. Insert the Windows installation disk or USB drive into the computer and restart it.
  2. Select "System Recovery Options" when prompted.
  3. In the recovery menu, open "Command Prompt".
  4. Enter the following commands, pressing Enter after each one:
bootrec /FixMbr
bootrec /FixBoot
bootrec /RebuildBcd

Once completed, close the command prompt and restart your computer.

This method usually resolves the "Bootmgr is compressed" error.

2. Disabling Disk Compression

If you can access the operating system (for example, if the error appears after a reboot but does not block startup), try disabling compression on the disk where Bootmgr is located:

  1. Open "This PC" and right-click on the system drive (usually C:).
  2. Select "Properties" from the menu.
  3. Uncheck "Compress this drive to save disk space".
  4. Click "Apply" and restart your computer.

3. Using Command Prompt to Remove Compression from the Bootmgr File

If the error prevents you from accessing the system, you can try removing compression directly from the Bootmgr file:

  1. Boot from the installation disk and open the command prompt.
  2. Enter the following command:
compact /U C:\bootmgr

This command will remove compression from the Bootmgr file on the system drive (usually C:).

  1. Restart your computer.

4. Checking and Repairing System Files

Sometimes, the error occurs due to corrupted system files. Use the SFC command to repair them:

  1. Boot into the command prompt from the installation disk.
  2. Enter the following command:
sfc /scannow

This command checks system files and replaces any corrupted ones with original copies.

What to Do if the Problem Persists?

If none of the methods work, consider other options, such as a full reinstallation of the operating system. You may also consult a professional to perform a deeper analysis of the hard drive and system status.