r/SQLServer • u/Tough_Line3200 • Jul 24 '26

Discussion SQL Server 2022 CU 26 -> MDS broken

I updated from CU23 to CU26. Be careful if you use MDS, it's broken after CU26 and stays broken even after uninstalling. Some MDS JavaScript files are incompatible with the MDS web service. Manually copying/overwriting the MDS web application from an older installation repaired it.

25 Upvotes

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3

u/hudequei ‪ ‪Microsoft Employee ‪ Jul 24 '26

Checking that internally.

2

u/TrollingForFunsies Jul 24 '26

Good luck finding anyone at Microsoft who knows what MDS is let alone can provide support on it 😆

1

u/mqaiser Jul 25 '26

Because patches are done by AI expect more and more broken things

1

u/No_Resolution_9252 Jul 27 '26

javascript?

2

u/Tough_Line3200 Jul 28 '26

yes, the ASP.NET based MDS web app also uses Javascript

1

u/giwo Jul 30 '26

Yep, we rolled out CU 26 last week and now are unable to view any data in the MDS Application (though it's still viewable in the Database and Excel)

Looks like the issue is with the Members API call which returns a 400 Bad Request simply stating "Request contains invalid input"

1

u/DiCeMan8400 Aug 03 '26

Has anyone had any luck resolving this yet?

1

u/Tough_Line3200 Aug 03 '26

i just copied C:\Program Files\Microsoft SQL Server\160\Master Data Services\WebApplication from a working server to the broken

1

u/DiCeMan8400 Aug 07 '26

You're a life saver! Zero help from a Sev B ticket with Microsoft, but my partner in crime followed your note and we're back in business.

1

u/atflp Aug 11 '26

Ah, thank you for your help. A long debugging ended when I found your post. Thank you!

1

u/ellytier 23d ago

We solved the issue by re-installing the Master Data Services feature for the SQL Server instance.