Common AdGuard installer errors

This article contains some of the most common errors that you can encounter during the AdGuard for Windows installation, and possible ways to solve them.

Error 5: Access Denied

This error occurs when there's something wrong with permissions. There may be several different reasons why AdGuard installer doesn't have the permissions it requires to properly finish the installation process. You can try the following steps:

  • Temporarily disable your antiviruses. Some of them may interfere with the installation, depending on the severity of their settings.

  • Choose a different installation folder. It is possible that the current installation folder has some access restrictions. Also make sure you don't select an external drive, a virtual drive, etc.

  • Reboot your computer. Sometimes the permission issues are temporary and can be solved by restarting the PC.


Error 112: Disk is full, Error 1632: Temporary folder full or inaccessible

These are two different errors with very similar solutions. As their names suggest, AdGuard installer didn't find enough disk space to complete the installation. There are several things you can attempt to fix the problem:

  • Uninstall some programs or delete unnecessary files from the drive you were trying to install AdGuard to.

  • Download, install, and run AdwCleaner, a free piece of software by Malwarebytes. It will, among other things, clean your system from all kinds of extra "leftover" files that remain after incorrectly uninstall programs and such. It will help clean up some disk space.

  • Reboot your computer. Sometimes temporary files can take up a considerable amount of disk space, and restarting your PC is the most reliable way to get rid of them.

Error 1601: Windows Installer is not accessible

You could say this is a particular sub-case of Error 1603. The possible solutions are similar:

  • Start and re-register Microsoft Installer service. It requires some work.

    1) Press Win + R and enter "services.msc.
    2) Find in the list and double click on Windows Installer.
    3) Hit Start button under Service status and hit OK. If the service status is running, you should click on Stop first and then hit Start.
    4) Press
    Win + R, type and enter "
    msiexec /unregister and hit Enter.
    5) Press Win + R again, type and enter "
    msiexec /regserver* and hit Enter**

  • Reboot the PC and start the installation all over again. Sometiemes that's enough to fix the problem.

Error 1602: Canceled by user

If you got this error code, chances are you have interrupted the installation process manually in one way or another. What you can do is:

  • Don't close the installer window. When the installation is complete, it will close automatically.

  • If a dialogue window pops up during the installation, hit "Yes" to grant the installer the required permissions. Clicking on "No" will cancel he installation.

  • Don't start other processes while the installation process is going on.

Error 1603: Fatal error during installation

The error sounds scarier than it actually is. In reality, this is a rather generic error that can have many different causes, and some of them are easily fixed. Try the following solutions:

  • Choose a different installation folder. It is possible that the current installation folder has some access restrictions. Also make sure you don't select an external drive, a virtual drive, etc.

  • Uninstall AdGuard using our special uninstall tool and then repeat the installation.

  • Start and re-register Microsoft Installer service. It requires some work.

    1) Press Win + R and enter "services.msc.
    2) Find in the list and double click on Windows Installer.
    3) Hit Start button under Service status and hit OK. If the service status is running, you should click on Stop first and then hit Start.
    4) Press Win + R, type and enter "msiexec /unregister and hit Enter.
    5) Press Win + R again, type and enter "msiexec /regserver and hit Enter

  • Acquire full permissions on the drive for installation. It is possible that the error 1603 occurs because you don’t have full permissions on the file location. It's also not as easy as some of the other solutions:

    1) Open File Explorer, right click on the drive containing the installation location and select Properties.
    2) Go to Security tab and click on Edit.
    3) Single click on SYSTEM and ensure that the Allow box of every item in Permissions for SYSTEM is checked (if it is checkable). Do the same check for Administrators.
    4) Click on OK to go back to Properties dialog. Then click on Advanced.
    5) Click on Change Permissions.
    6) On Permissions tab, double click on Administrators.
    7) Select This folder, subfolders and files for Applies to field and tick all the available Basic permissions. After that hit OK.
    8) Do the same operation above (from item 7) for SYSTEM.
    9) Click on OK all the way out. Try installing AdGuard again.

Error 1618: Another installation is already in progress

This error occurs when there are several instances of AdGuard installer launched at the same time. What to do if you get this error:

  • Reboot your PC and start the installer again. When you restart the computer, all ongoing processes will stop, including all copies of the installer.

  • Don't make multiple clicks on the installer even if doesn't start right away. Sometimes it may take a few seconds to display the installer UI.

Error 1638: Another version of this product is already installed

It's very likely that you've already installed AdGuard before.

  • Check if AdGuard is already installed on your computer. You can do it by pressing the Win key and typing in AdGuard.

  • Maybe there's some leftover files from a previous AdGuard installation. Uninstall AdGuard using our special uninstall tool and then repeat the installation.

Other errors

If you've encountered an error that's not listed above, it is possible that we can solve it by ourselves. But in order to do that, we need log files from you. Please perform the following steps:

  • Find and archive AdGuard installation logs as it is described in this article.

  • Find and save to disk Event Viewer logs. This article explains how to do that.

  • Please email all these files from two previous steps to support@adguard.com and describe the problem in the message body. Our tech support agents will reply to you as soon as possible.