SQL Server | Other
Additional SQL Server features and topics not covered by specific categories
It seems to be fixed in CU 27
Master Data Services web app renders empty after SQL Server CU26 update
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Simon Lenk
10
Reputation points
Hi everyone,
SQL Server 2022 CU26 appears to break Master Data Services web application.
After patching to CU26 (16.0.4265.3), the MDS web application loads, but is completely empty.
The MDS database and data remain intact and are visible through SQL views/tables. Uninstalling CU26 does not resolve the issue because MDS web application assemblies in Master Data Services\WebApplication\bin remain at version 16.0.4265.3.
A temporary workaround is replacing the newer Version of the files in "...\WebApplication\bin" by the older version.
I'm assuming that this is an actual bug in the CU26 patch, therefore is there any possibility of including a fix in the next CUs?
Best regards,
Simon
SQL Server | Other
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sarath m 5 Reputation points2026-09-19T17:04:22.7166667+00:00 Hello, I am facing same issue on my side as well. I am getting MDS API call error 400 bad request while opening any of the entities in MDS website. Additionally I am not able to create any new entity or attributes in MDS. Did you find any solution for this issue?
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Erland Sommarskog 137.7K Reputation points MVP Volunteer Moderator2026-09-19T18:21:14.58+00:00 Did you test this with CU27? According the post from Henrik Munch, this seems to be fixed in CU27. (I don't use MDS myself, so I cannot speak from my own experience.)
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Henrik Munch 0 Reputation points2026-09-21T11:04:14.78+00:00 We have justed installed CU27 on our other SQL2022 Environments and I can confirm that the issue has been resolved for us by this.
Nothing in the CU27 descriptions specifically states anything about MDS as far as I recall.
But after completely clearing our browsers cache, we can now see the data in a model in the Explorer. -
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Peter Nagy 0 Reputation points2026-09-28T07:07:18.8466667+00:00 I’ve also experienced that CU27 fixes this issue. However, even after applying CU26 and CU27, it’s still not possible to create a new entity, and the attributes are not listed for an existing entity — which also means that new attributes cannot be created through the Web interface.
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Henrik Munch 0 Reputation points
2026-09-17T12:08:37.3633333+00:00 -
Simon Lenk 10 Reputation points
2026-09-21T05:34:41.6133333+00:00 Hi Henrik,
I patched the server last week with the CU27 (16.0.4295.3) but I needed to use the same workaround as in the CU before.
Where did you get the info of it being resolved?Best,
Simon -
sarath m 5 Reputation points
2026-09-25T15:16:20.5733333+00:00 Issue has been resolved after CU27 patch. I can see the data in entities after the patch.
But I have a problem in creating entities and attributes in MDS. It is throwing API 400 bad request error. Anyone else facing this issue?
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Erland Sommarskog 137.7K Reputation points MVP Volunteer Moderator
2026-09-03T12:10:34.4533333+00:00 Master Data Services is not the hottest component in the SQL Server portfolio, and I seem to recall that it is not included with SQL 2025. But breaking and dropping it in a CU sounds overly brutal.
I would recommend you to open a support case. I think that would be the best way to make Microsoft aware of the issue.
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Simon Lenk 10 Reputation points
2026-09-21T05:31:47.8166667+00:00 Hi Erland,
I currently only have a support contract with MS Office and they referred me back to this Q&A. Therefore I could not open a support case in which it might be addressed.
Best,
Simon
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Erland Sommarskog 137.7K Reputation points MVP Volunteer Moderator
2026-09-21T06:48:54.3366667+00:00 The other alternative is to report it as a bug on https://feedback.azure.com/d365community/forum/04fe6ee0-3b25-ec11-b6e6-000d3a4f0da0. However, this is more to let Microsoft know about the issue, and they will triage the issue as they see fit. On the one hand, if something is broken, they should fix it. On the other hand, MDS is a product they have abandoned. MDS is not included in SQL 2025, as I recall.
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Simon Lenk 10 Reputation points
2026-09-21T06:51:35.64+00:00 Hi Erland,
will do so. Thank you for your support!Best,
Simon
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