why has vista stopped automatic updates?

Well Karen, there is no internal mrt.log or other internal File created with execute per 7-Zip. I tried both July x64 versions, the delta (smaller) and the larger version. When I ran the delta, there was no activity with Task Manager. When I ran the larger version, it did appear in Task Manager for about one minute, then an error message appeared saying "This operating system is not supported by the Microsoft Malicious Software Removal Tool". However, it did replace my April System32 Version of mrt.exe with Version 5.50.14000.0. So, in my case with the error message, I don't think it ran. I'll run System Restore to return to my previous condition. An interesting experiment at least...OUgrad

I'll try the MSRT manual download tomorrow. If it updates in System32, I'll copy the File, use 7-Zip to extract the File copy contents and see if there is an internal log File about installing as well as my April 14 Version first. The normal mrt.log File may no longer be linked in Vista.

EDIT - Another thing I'll do tomorrow is open Task Manager to show all Processes so I can watch how long MSRT Runs - probably 5-10 minutes before it disappears from the list. Clicking Image Name in Processes alphabetizes the Processes (ascending or descending) so they don't jump around - easier to watch.

Just to clarify, I got the C:\Windows/System32/mrt.exe that i last executed (v5.50) from the Microsoft Update Catalog (KB890830), i.e., the one listed for Windows Server 2008,  executing it on my Vista x86.  The 32-bit one that is available via the Microsoft Download Center gave me a N/A, if I recall.  

I am curious to hear about the file contents regarding a internal mrt.log and what you see via the Task Manager.

Yes Karen, the mrt.exe File is compressed in every Windows Version, likely because of its' large size. I can't imagine that File being updated in System32 unless it executed. Perhaps someone else can verify. Agree that the mrt.exe File Version also confirms it is current. The last time I ran mrt.exe was April 14. That Version is 5.47.13703.0 from the Details Tab in File Properties. I just got three Microsoft Office 2007 Updates when I ran WU manually, Office Suites, Excel and Compatibility, nothing else. I'll try the MSRT manual download tomorrow. If it updates in System32, I'll copy the File, use 7-Zip to extract the File copy contents and see if there is an internal log File about installing as well as my April 14 Version first. The normal mrt.log File may no longer be linked in Vista.

EDIT - Another thing I'll do tomorrow is open Task Manager to show all Processes so I can watch how long MSRT Runs - probably 5-10 minutes before it disappears from the list. Clicking Image Name in Processes alphabetizes the Processes (ascending or descending) so they don't jump around - easier to watch.

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)??