Revit 2026.4 crashes when RevitLookup 2026.0.1 is loaded and another add-in refreshes Ribbon/QAT

[Akmal1628]

RevitLookup version

2026.0.1

Steps to reproduce

Revit version

Autodesk Revit 2026.4.0.32
Build: 20251103_1515(x64)

RevitLookup version

RevitLookup 2026.0.1
File version: 2026.0.1.0

Description

Revit crashes in Revit 2026.4 when RevitLookup is loaded and another add-in dynamically refreshes the Ribbon/QAT.

I have a third-party add-in (mySchema) with a WPF settings window.
Opening that settings command and triggering Ribbon/QAT refresh causes Revit to crash.

The same workflow becomes stable after disabling RevitLookup.

What makes me think RevitLookup is involved

The Revit journal shows an explicit assembly version conflict for RevitLookup.dll before the crash:

• RevitAPIUI 26.2.0.0 conflicts with preloaded 26.4.0.0
• RevitAPI 26.2.0.0 conflicts with preloaded 26.4.0.0
• UIFrameworkServices 26.0.4.0 conflicts with preloaded 26.4.0.0
• UIFramework 26.0.4.0 conflicts with preloaded 26.4.0.0
• netstandard 2.0.0.0 conflicts with preloaded 2.1.0.0

After that, Revit reports:

• .NET exception 0xe0434352
• ANTECEDENT: editor ArrowEditor
• crash protection starts, then Revit exits

Repro steps

1. Start Revit 2026.4.
2. Load RevitLookup 2026.0.1.
3. Load another add-in that dynamically updates Ribbon/QAT through ExternalEvent.
4. Open that add-in’s settings window.
5. Trigger Ribbon refresh / reopen the settings command a couple of times.
6. Revit crashes.

Expected behavior

Revit should remain stable even if another add-in updates Ribbon/QAT dynamically.

Actual behavior

Revit crashes after the external command / ribbon refresh sequence.

Additional note

This may be related to the Revit 2026 add-in isolation change mentioned in the 2026.0.1 release notes.

Temporary workaround

Disabling RevitLookup removes the crash in my environment.

После отключения RevitLookup падение исчезает

✔️ Expected Behavior

journal.0032.0001.dmp
journal.0032.txt
journal.0032.txt.copy.txt
journal.0032.worker1.log

❌ Actual Behavior

No response

Other Software

No response

[Nice3point]

Load another add-in that dynamically updates Ribbon/QAT through ExternalEvent.

this is your addin ? can you send the code of "dynamic update" or "mySchema" dll ?. It creates a new buttons, changes text, or what? need some description to understand the process or screen recording. Logs empty