Every time I try to install the update, it can't find BOINC.msi and cancels the installation. This is the BOINC it claims to be downloaded in.... Er, some directory other than %temp%. Sorry, I just tried again to get the error and it seems to have succeeded because I reinstalled / repaired using an older version, 7.2.

Let me reboot and see if it worked, if so, then your installer might not be working correctly, or presenting an odd useless error that would confuse people.

Every time I try to install the update, it can't find BOINC.msi and cancels the installation. This is the BOINC it claims to be downloaded in.... Er, some directory other than %temp%. Sorry, I just tried again to get the error and it seems to have succeeded because I reinstalled / repaired using an older version, 7.2.

Let me reboot and see if it worked, if so, then your installer might not be working correctly, or presenting an odd useless error that would confuse people.

http://boinc.berkeley.edu/wiki/Advanced_FAQ

 Problems installing BOINC (Windows)

In rare cases, installation may fail because of an existing installation of BOINC. If this happens:

    Quit BOINC if it's running, and uninstall BOINC using Start/Control Panel/Add and remove programs. Install the new version again.
    If that fails, reinstall the version of BOINC you were previously running (you can get an older version from the download page). Uninstall it, then install the new version.
    If that fails, download the Windows Install Clean Up utility from Microsoft and run it. The old BOINC version shows up as either BOINC.msi or as a corrupt icon .msi (it'll be the top option). Click on it to select, then click Remove and Exit. Reboot your computer. Install the new version. (Warning: leave all other .msi files as they are, otherwise you will have problems uninstalling other programs). 

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The Windows Installer Cleanup Utility (MSICUU2.exe) is no longer available from Microsoft.

Finally managed to get it installed.

I've tried the above tips and still can't get it installed. Not even the last version (7.2.42). I tried to install it on 2 different machines with the same result so now 2 of my PCs are no longer running BOINC. Any help would be appreciated. If you want any additional information please ask. I will supply all information I can.

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Additional information. One machine is Windows 7 Ultimate 64bit and the other machine is Windows 7 Ultimate 32bit

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The issue is due to a corrupt Microsoft Installer database which stores information about every .msi file used (as most installers are packaged with). This corruption loses the location of the current version of MSI and refuses allow anything to be upgraded or installed from that MSI name. This particular bug/corruption mostly crops up when an application is installed from a network or removable drive location.

There are a few ways this can be fixed:

1) Try to obtain the same version MSI (e.g. if you currently have BOINC v5.10.45 installed, use that same version MSI file), and put it in the same exact location the installer is prompting you to define.

2) Obtain the Microsoft Installer Cleanup Utility from a source other than Microsoft to automate the cleanup process.

3) Manually search the Windows Registry for all references to BOINC.MSI, then delete the entire product key. For example, if BOINC.MSI is listed in HKEY_CURRENT_USER\Software\Microsoft\Installer\Products\2F1E4AFCA09053346AB0898DCE968E14\SourceList, delete the entire 2F1E... key. Do this for all keys in the registry that point to BOINC.MSI.


WARNING! Incorrectly editing your Windows registry can result in a non-operable system. If you do not feel comfortable doing this, please do not follow step 3.

http://www.majorgeeks.com/files/details/windows_installer_cleanup_utility.html

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No need for the Microsoft Installer Cleanup Utility, and potentially delete something you didn't want to delete, as Microsoft has its own utility to fix these things these days: http://support2.microsoft.com/mats/program_install_and_uninstall.

The rest of the tips on how to fix this are in this BOINC FAQ.

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