"You must enable rollback to continue with setup" error message appears when you install or remove .NET Framework

When you install or remove the .NET Framework, you may receive the following error message:

This error occurs because the rollback feature of the Microsoft Windows Installer is disabled. The .NET Framework Setup program requires commit custom actions for proper installation. Rollback and commit custom actions do not run when rollback is disabled.

Rollback is disabled in the DisableRollback policy in the registry. The DisableRollback policy value may have been set by an administrator. Microsoft recommends that administrators do not disable rollback unless this is necessary.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
There are two places in the registry where the DisableRollback policy value can be set. To resolve this problem, you must find out where the DisableRollback policy was set and remove or disable the setting.

To find out whether this property exists in your registry, run C:\Regedit.exe and check the following locations: If the DisableRollback key exists and has a value of "1", delete the key or set the value of the key to "0". (You can also set DisableRollback through command-line instructions.) Microsoft recommends that administrators and developers not set this property if they use command line instructions to run Setup, or Setup will not work.

This behavior is by design.

For more information about the DisableRollback policy value, visit the following Microsoft Developer Network (MSDN) Web site: