I found out here that there's a way to fix WU being stuck on checking on updates after installing SP2 for Office 2010 on Vista (and XP, well kinda, read at the end for more info). 

Note: This problem is unique to Windows XP and Vista, 7 and newer don't have this issue.

 

First, install SP2 for Office 2010 if you don't have it installed yet (you should see it on WU already):

For x86 (32-bit):

SP2 for Office 2010 x86

For x64 (64-bit):

SP2 for Office 2010 x64

 

If you now have SP2 installed or already had it installed beforehand:

To fix the WU issue, you'll have to download and install these two updates for Office 2010 SP2 prior to checking for updates (Office 2010 SP2 must be installed already!):

For x86 (32-bit):

Security Update for Microsoft Word 2010 (KB4493218) 32-Bit Edition and Security Update for Microsoft Excel 2010 (KB3017810) 32-Bit Edition

For x64 (64-bit):

Security Update for Microsoft Word 2010 (KB4493218) 64-Bit Edition and Security Update for Microsoft Excel 2010 (KB3017810) 64-Bit Edition

After installing the two updates, it's recommended to restart your computer.

 

If you installed the two updates:

Open Windows/Microsoft Update and check for updates, you should see updates for Office 2010 SP2 after waiting a while. Yay! 

You should now update Office 2010 to its final updates. But if you're on XP, read below (hint: it's not good news).

 

This has been successfully tested on a Vista VM with Office 2010 SP2 installed.

 

If you're doing this on XP, be aware that the newer updates for Office 2010 SP2 break the Office 2010 programs (Word, PowerPoint, etc.) on XP.

Go here for more info

Personally, on XP, I stick with Office 2007 because those newer Office 2010 updates break Office, as stated above.

Edited December 8, 20223 yr by WinGlass

On 11/25/2022 at 12:44 PM, WinGlass said:

If you're doing this on XP, be aware that the newer updates for Office 2010 SP2 break the Office 2010 programs (Word, PowerPoint, etc.) on XP.

Go here for more info

Oh btw, not all of the newer Office 2010 updates break Office on XP, I think it's most of them that do. I also haven't tested it on XP, this is from what I know.

Edited December 8, 20223 yr by WinGlass

FYI, it can take like, an hour to check for updates after the two updates and SP2 are installed.

It's wuaueng.dll regression for calculating updates metadata chain, specifically these functions

CUpdatesToPruneList::PopulateSupersedenceInfo
CUpdatesToPruneList::AddSupersedenceInfoIfNeeded

they fixed it for Win 7-8.1, but they never backported the fix for Vista/Server 2008