5 Easy Steps to Fix BOOTMGR Compressed Error

The error message “BOOTMGR is compressed Press Ctrl+Alt+Del to restart” may appear when you start up your computer. If you press Ctrl+Alt+Del that just restarts the computer and then displays the same error message again. I saw this error recently on a customer’s computer and thought I’d share how to fix it. The error can affect Windows 10, 8, 7, Vista and XP computers.

What Is BOOTMGR?

BOOTMGR refers to the Boot Manager which is an important Windows system file. If it is compressed, it can’t be used, and Windows can’t start or boot up when this happens. The file must therefore first be uncompressed for Windows to be able to boot properly. File compression used to be a good way to save hard drive space back in the days when hard drives were maybe 2 or 20 GB in size, However, modern drives offer thousands of GB storage so there really is no need to compress files.

Why is BOOTMGR Compressed?

There are two likely reasons that it may have been compressed.

1. You installed a Speed Booster or System Optimizer type of program perhaps one with grand claims of boosting performance and with a super-duper registry cleaner thrown in. See do I need a registry cleaner and the short answer is No.

Such a program often causes this problem by compressing the whole of the system partition usually the C: drive to save space this is including the crucial BOOTMGR file. This is what happened in my customer’s case. File compression even when done properly may slow down system performance anyway so it is a lousy thing for a speed booster utility to do.

2. You manually compressed the whole of the system partition via the drive’s Properties window.

The fixes for Windows 10 and all earlier versions of Windows are very similar in that they require you to recreate the BOOTMGR file. Boot into the System Recovery Options using the preinstalled Advanced Boot Options or a Windows installation/recovery DVD. Select Startup Repair and wait until the repair attempt completes. If successful you can then restart the computer and Windows may boot up normally. If the repairs fail and/or the computer does not restart into Windows normally, proceed with the 5-step below:

For Windows 10 and below but not including XP and Older complete these steps.

Step 1

Boot into the System Recovery Options again but this time select Command Prompt instead of Startup Repair this will take you to a windows Command Prompt.

[Note: if using RAID for multiple hard drives you may not see your version of Windows listed in System Recovery Options, during the loading of the recovery process. In this case you would need to press ‘Load Drivers’ and browse to your RAID drivers so that your version of Windows can be listed.

Step 2

Type bootrec /fixmbr and press Enter.

Step 3

Type bootrec /fixboot and press Enter.

Step 4

Type bootrec /rebuildbcd and press Enter. Type Y and press Enter if asked to add the installation to the boot list:

Bootrec commands

Step 5

Now type Exit and press Enter to restart the computer. The error message should not appear and Windows should start up normally.

For Windows XP follow these steps.

You will need to have a bootable XP installation CD available.

Step 1

Log into the Recovery Console command prompt by following steps A to F in my article on fixing ntldr. You should now be in the C:\Windows directory.

Step 2

Type fixmbr and press Enter. Press y to accept the warning and proceed:

Fixmbr

Step 3

Type fixboot and press Enter. Press y to to confirm and proceed:

Fixboot

Step 4

Type Exit and press Enter to restart the computer.

Step 5

The error message should not appear, and Windows should start up normally.

Alternative BOOTMGR Is Compressed Fix

This fix should not be required but, if for some reason the previous fixes failed to resolve the problem, you may need to decompress all files on the system partition manually.

Log into the System Recovery Options \ Command Prompt (Vista/Windows 7/8/10) or Recovery Console command prompt (XP).

Type compact /u /a c:\*.* and press Enter. The command may take a long time (hours) to complete on a very large drive – leave it until finished.

Once it finishes decompressing all files, type Exit and press Enter to restart the computer. The error message should not appear, and Windows should start up normally.

Note: if your Windows system drive is not c: then change the c in the command to your drive letter e.g. d:\

What Does the Compact Command Do?

This command decompresses (/u) all files (*.*) on the c:\ drive including hidden and system files (/a).

Conclusion

Unfortunately, Windows does nothing to prevent an optimizing program or a user from compressing Bootmgr even though it means that Windows will not boot Windows assumes that the user knows what they are doing.

However, this problem is relatively straightforward to fix and easy to avoid in future, but in my option don’t use system optimizing utilities that may compress the Windows system partition and don’t try to compress it manually.