How do I completely uninstall BOINC 6 and 7, on Windows / Uninstall to prepare for reinstall?

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First off you will have to remove your BOINC installation by going Start->Control Panel->Add/Remove Programs->BOINC->Remove

If by chance you get an error message that the MSI file cannot be found, or that the network resource is unavailable, see this FAQ for options around that.

Once you have uninstalled BOINC, you can delete the left-over BOINC executable directory. Default paths for it can be found in this FAQ. Leave the BOINC Data directory alone for now. We'll come to that in point 4.

All of the points below and some more things are included in a batch file that I made that will automate the process. It will still assume you uninstalled BOINC through Add/Remove Programs prior to you starting it. See Point 5 for details.




After you uninstalled BOINC through Start->Control Panel->Add/Remove Programs, remnants of BOINC will still linger on your system. The following steps will remove these remnants completely. But we're starting with the first 3 steps that still allow you to reinstall BOINC 6 at a later date, or as a "clean solution" to get rid of possible account related bugs.


1. The User Accounts and Groups To cleanup the newly created users and groups on anything else than Windows XP Home do the following:

  • Click on the 'Start' button).
  • Right-click on 'My Computer' and select 'Manage'.
  • Expand the 'Local Users and Groups' tree node.
  • Click on the Groups tree node.
  • Delete the 'boinc_admins' group.
  • Delete the 'boinc_users' group.
  • Delete the 'boinc_projects' group.
  • Click on the Users tree node.
  • Delete the 'boinc_master' user account.
  • Delete the 'boinc_project' user account.


Windows XP Home, Vista Home and 7 Home don't have the Local Users and Groups tree node, so here we have to do it differently.

  • Click on the 'Start' button.
  • Click on 'All Programs'.
  • Click on '(Desktop-)Accessories'.
  • Right-click on 'Command Prompt'.
  • Choose 'Run as administrator' and confirm.
  • In the command prompt window that opened, type:
    • net user boinc_master /delete (press Enter).
    • net user boinc_project /delete (press Enter).
    • net localgroup boinc_admins /delete (press Enter).
    • net localgroup boinc_projects /delete (press Enter).
    • net localgroup boinc_users /delete (press Enter).


2. Cleanup User Rights Assignments To cleanup the newly assigned user rights do the following (again, only for all Windows version but Windows XP Home):

  • Click on the 'Start' button.
  • (Click on 'Settings').
  • (Click on 'Control Panel').
  • Launch the 'Administrative Tools' control panel applet.
  • Launch the 'Local Security Policy' application.
  • Expand the 'Local Policies' tree node.
  • Click on the 'User Rights Assignment' node.


Open each user right that contains a boinc_master or boinc_project entry, and remove those from the lists.

Windows XP Home, Windows Vista Home and Windows 7 Home do not have the Local Security Policy. It may be possible that you can remove the entries the installer made from the registry, but it's at this point unknown where it puts these entries in the registry.

(The developers haven't come back to me about this, so I really don't know what the installer does with those entries. Perhaps it silently drops them).


3. Cleanup Setup Registry Entries To cleanup the newly created registry entries do the following:

  • Launch 'regedit.exe' from the Start\Run menu item.


  • Expand the 'HKEY_LOCAL_MACHINE' entry.
  • Expand the 'Software' entry.
  • Expand the 'Space Sciences Laboratory, U.C. Berkeley' entry.
  • Delete the 'BOINC Setup' entry.
  • Delete the 'Space Sciences Laboratory, U.C. Berkeley' key.


  • Go back to the 'HKEY_LOCAL_MACHINE' entry.
  • Expand the 'SYSTEM' entry.
  • Expand the 'CurrentControlSet' entry.
  • Expand the 'Services' entry.
  • Delete the 'BOINC' entry, if it exists.


  • Go back to the 'HKEY_LOCAL_MACHINE' entry.
  • Expand the 'Software' entry.
  • Expand the 'Microsoft' entry.
  • Expand the 'Windows' entry.
  • Expand the 'CurrentVersion' entry.
  • Expand the 'Run' entry.
  • Delete 'boincmgr', if it exists.
  • Delete 'boinctray', if it exists.


  • Expand the 'HKEY_CURRENT_USER' entry.
  • Expand the 'Software' entry.
  • Expand the 'Space Sciences Laboratory, U.C. Berkeley' entry.
  • Delete the 'BOINC Manager' entry.
  • Delete the 'BOINC Screensaver' entry.
  • Delete the 'Space Sciences Laboratory, U.C. Berkeley' entry.


Exit regedit.


Now then, if you really want to get rid of BOINC completely, you will need to remove the Data directory as well.

If you're just going for a reinstall, move the directory with all contents to C:\Program Files\BOINC\, where the installer can pick it up again. Else...


4. The Data Directory

By default BOINC installed the data directory in:

Windows 2000/XP: C:\Documents and Settings\All Users\Application Data\BOINC\
Windows Vista/Windows 7: C:\ProgramData\BOINC\

These directories can be hidden, so make sure you allow for Show hidden files and folders.

Delete this directory and all files and sub-directories.

That will clean BOINC off your system. You can now reboot to get rid of the remnants still in volatile memory.


Original writer Original FAQ Date
Jorden 490 27-Apr-2009