PBIRS January 2026 New Button Slicer Bug

I noticed a much more serious bug with the January 2026 version of the reporting server. If you look at the contents of the "C:\Program Files\Microsoft Power BI Report Server\PBIRS\LogFiles\" directory, it's overflowing with large files "Msmdsrv.SQLDmpr.*.log", "Msmdsrv.SQLDmpr.*.mdmp" and "SQLDUMPER_ERRORLOG.log". After a while, the disk space may run out.

Hi pashock ,

This issue could be related to a version difference between Power BI Desktop and the environment you're publishing to. Even though both show January 2026, the regular monthly Power BI Desktop (2.150.x) and Power BI Report Server (1.25.x) don’t always support the exact same visual features, especially newer visuals like the Button Slicer. Because of this, Report Server may not fully recognize the updated formatting settings and can fall back to default styling after publishing.

Based on similar scenarios, you can try the following checks. First, use the Power BI Desktop for Report Server version that matches your Report Server build, then open the report, recreate or reformat the slicer, and republish. If the slicer is using a preview feature, disable it by Preview Features, restart Desktop, and publish again. If the issue still continues, try deleting and rebuilding the slicer in the correct version and temporarily removing any custom theme to rule out theme compatibility issues. Going through these steps should help reduce the chances of formatting problems after publishing.

Hi,  Anonymous,
The versions match and the visuals are GA. I created the report again, but it didn’t help.

I came here to report the exact same issue with the exact same versions for both PBIRS and Desktop RS. I also tried the steps to fix it but it did not work (enabling/disabling Preview Features does not seem to be available for Desktop RS).

The button slicer is recognized but it's like I can't use color, only black and white.

Hello pashock, 

This is expected behavior in PBIRS January 2026.

The new Button Slicer uses visual and formatting features that are supported in Power BI Desktop, but not fully supported in Power BI Report Server yet.

Microsoft documents that PBIRS does not have full feature parity with Desktop or the Power BI service. New visuals and newer formatting options often render correctly in Desktop but fall back to a basic style after publishing to PBIRS.

What you are seeing:

• Correct formatting in Desktop
• Loss of custom formatting after publish
• Default styling applied on the server

This is a server limitation, not a report issue.

Microsoft reference that supports this:

Power BI Report Server has a slower release cycle and supports a subset of Desktop features. Not all visuals and formatting options available in Desktop are supported when published to PBIRS.

Official doc:
Compare Power BI Report Server and the Power BI service 

Current workarounds:

• Use a standard slicer instead of Button Slicer
• Avoid advanced formatting like selected state styling, custom fills, or borders
• Keep slicer formatting close to default

Until PBIRS adds full support for the Button Slicer formatting, this behavior will continue.

pashock ,

MS has released a fix for log file and button slicer, but New Card visual still has bugs.

• Version: 1.25.9552.1669 (build 15.0.1120.119), Released: February 25, 2026
  • Fixed issue where certain types of Power BI Reports lead to excessive crash dumps being created.

Change log for Power BI Report Server - Power BI | Microsoft Learn