why has vista stopped automatic updates?

RE: Is there a way to tell which is true -- a) it did not execute   b) it executed, but did not record it in the MSRT log?

The only two ideas I have to confirm MSRT ran are (1) the mrt.log File in C:\Windows\Debug and (2) check the Date Modified under Properties, General Tab for the C:\Windows\System32\mrt.exe File. Date Modified changes each time it runs.

Dear OUgrad,

I checked the C:\Windows\Debug\mrt.log and the last record is for a scan run on April 12, 2017 from Windows Update of v5.47 (April version)  --  the last official Microsoft "Patch Tuesday" month for support of Vista.  However, the Properties > General tab for C:\Windows\System32\mrt.exe shows that mrt.exe executed again on July 19.  I look at the info under the Details tab and it says that it was v.5.50, the last one of the three Windows Server 2008 MSRT tools (v5.48, v5.49, v5.50) that I ran on July 19.  So, I am fairly certain now that b) is the answer:  the MSRT tool (i.e., one in the Microsoft Update Catalog for KB890830 for Windows Server 2008) will execute on a Vista x86, but it is not recorded in the mrt.log.  

Thanks for the info on checking the tabs under the Properties of C:\Windows\System32\mrt.exe and giving me directions on how to find the answer :-)

One more question:  the mrt.exe file is in blue, which means it was saved as a compressed file, which I am guessing was done automatically when it was extracted from the downloaded KB890830 file.   Even though compressed, can I assume that it ran?  Or alternatively, maybe, the date on the file is the date it was saved (but not necessarily run)??

Confirmed - MSRT is still working with Vista in Windows Update if set to Install Updates Automatically (and possibly the other two Settings above Never Check). One of several friends I've helped keep Vista up-to-date with shows MSRT ran May and June in Update History after the April 11 Update FIX. June MSRT ran before getting the June 13 update release done per this Discussion Thread. Interesting, MSRT ran, but none of the other June Updates. THEY had to be installed per this Thread. Regardless, I tell my "Vista" friends to leave their PC connected to the Internet at least 3 hours continuously once a week to make sure Windows Update has time to initiate the Install Updates Automatically Setting and at least get MSRT monthly. My Vista PC is rarely online with so many others in my "collection" :-) OUgra

I am really curious about your statement that MSRT is still working in Windows Update on a Vista x86 machine.  Windows Update has not delivered the MSRT since the April one on my Vista x86 machine. 

Yesterday, I tried to install the current version (v5.50) manually from https://www.microsoft.com/en-us/download/malicious-software-removal-tool-details.aspx but there was a message that the MSRT is not compatible with my system. 

So, I went to the Microsoft Update Catalog, searched for KB890830, and downloaded the May (v5.48), June (v5.49), and July (v5.50) MSRT for Windows Server 2008 (none is listed for Vista beyond 4/11/2017).  Other Window Server 2008 patches work on Vista x86, so I surmised that Windows Server 2008 KB890839 would work as well.

I clicked on each one by one to execute it. Each time the Account Control dialogue box appeared to "continue" and then the blue circle twirled, I didn't receive any message that the file would not execute.  But when I checked the MSRT log there is no record there of any of the three having actually executed.   So, either it did not execute or it executed, but the MSRT log did not record it. 

Is there a way to tell which is true -- a) it did not execute   b) it executed, but did not record it in the MSRT log?

I did not  pre-install these two July patches listed in the quote.  Instead I found them today in my list of three Windows Updates that the Windows Updater automatically delivered.  ...  Just saying here that it looks like it might not be necessary to pre-install.

I had the same thing happening on a Vista x64 machine, but I am experimenting with installing Windows Server 2008 security updates on that machine and had the Windows Server 2008 May updates installed, so I figured that was the reason why Windows Update ran fine. However, on my Vista x86 machine I did have to manually install KB3191897 and KB 3191894. Without those updates Windows Update was still searching after an hour had passed. I think it apparently depends on your specific machine whether manual installation is necessary or not.

I have a Vista x86 Ultimate 0/S and at the time that I said that I did not have to pre-install those two new July Office 2007 patches from VZ's 7-11-2017 posting, I did NOT have Windows Server 2008 updates installed.  If you didn't have any WS 2008 patches on your Vista x86 machine either, then, yes, there must be something different about your Vista x86 O/S and mine.

I did not  pre-install these two July patches listed in the quote.  Instead I found them today in my list of three Windows Updates that the Windows Updater automatically delivered.  ...  Just saying here that it looks like it might not be necessary to pre-install.

I had the same thing happening on a Vista x64 machine, but I am experimenting with installing Windows Server 2008 security updates on that machine and had the Windows Server 2008 May updates installed, so I figured that was the reason why Windows Update ran fine. However, on my Vista x86 machine I did have to manually install KB3191897 and KB 3191894. Without those updates Windows Update was still searching after an hour had passed. I think it apparently depends on your specific machine whether manual installation is necessary or not.