Whenever I try and install Reviver I get an 0x80070643 error (and says its caused by Contacts). I’ve used CCleaner, deleted all the Contacts folders etc I could find including in the registry (unless I’ve missed something), and still have this problem. No clue what to do now.
Do I have any options besides having to mess around with my OS (hoping it doesn’t have to come to that!). Any help would be nice, thanks.
0x80070643 is the ever-not-so-helpful “install failure” code. The Windows Essentials installer is ridiculously complex with a huge set of multiple installers running in parallel and other crazy tricks.
The installation log will be very useful here. Reviver will prompt you to open the folder of the log files after the installation fails, or you can simply get there yourself by pressing the 
R (Windows Key-R) to bring up the Run box, then copy and paste the following text and choose the OK button.
%ProgramData%\Microsoft\WLSetup\Logs
The newest log is what you’re after. I’m unsure if you’ll be able to paste what is probably a big text file here, feel free to email it to my messengerlogs@jonathankay.com email instead if you have trouble.
Also I’d highly suggest you use System Restore in Windows to restore to a restore point before the CCleaner/registry deletion attempts. In my past experiences and just on how the Microsoft Installer software works, this brute force method has made it increasingly time consuming to debugging install issues with the Essentials installer.
Late reply, sorry.
I’m now getting an error with a missing ‘wldlog.dll’ so the installer doesn’t even run.
I’ve attempted to download it but there’s only a 32 bit version which I’ve tried but doesn’t work.
Unsure what to do now.