When Revit starts, it loads all installed add-ins. If two add-ins reference conflicting versions of the same DLL library, Revit may fail to load one or both of them.
How to recognize a conflict
When a conflict occurs, Revit usually shows a warning dialog at startup — before the main window opens — naming the add-in that failed to load.
Other signs of a conflict:
The Pirros tab appears in the ribbon but specific buttons don't respond
Revit crashes immediately after opening a file
Pirros loads correctly but another add-in (e.g., pyRevit) stops working after installing Pirros
Step 1: Note which add-in the warning names
The startup dialog will tell you which add-in failed. Write down the exact name — this is the conflicting plugin, not necessarily Pirros itself.
Step 2: Temporarily disable the conflicting add-in
In Revit, go to Add-Ins → External Tools → Manage Add-ins.
Find the conflicting add-in in the list and select it.
Click Disable (for this session only, or always).
Restart Revit and verify Pirros loads correctly.
Step 3: Report the conflict
If disabling the other add-in resolves the problem, the conflict is a shared dependency version mismatch. Contact Pirros support with:
The name and version of the conflicting add-in
Your Revit version and Pirros plugin version
A screenshot of the startup warning message
Also contact the other plugin's support team — conflicts like this are often resolvable by updating either or both plugins.
FAQ
Q: Can I run Pirros and pyRevit at the same time?
A: Yes, most users do. Conflicts are version-specific. Keeping both on their latest versions is the best way to avoid them.
Q: A conflict appeared after a Pirros update. Is that a Pirros bug?
A: Possibly. Plugin updates can change the version of shared libraries they bundle, which can break compatibility with other add-ins that use the same library. Report it to Pirros support so it can be investigated.
Q: Can IT avoid these conflicts when deploying to multiple machines?
A: The safest approach is to test the full set of add-ins together on one machine before rolling out to the firm. See How to install or uninstall the Pirros plugin remotely for your staff.