License Manager initialization failed with error -200

I found a tool that could help testing if there is an incompatibility between two Revit plugins, it’s free and open source.

It allows you to disable all but one plugin easily and test if it works.
If it works alone then you can enable more plugins and test again until found if two plugins are not compatible.

To download and install please follow instructions found here:

  1. Download the tool from Bitbucket here.
  2. Find where you downloaded the zip file and unzip it.
  3. When unzipped, there will be a BIN folder; browse into the BIN folder then the Debug sub-folder.
  4. Run the tool by double-clicking on the exe file.
  5. In the window that opens, pick your version of Revit (or go with all if you like).
  6. The data grid will update to display all of the machine wide and the logged in user specific add-ins installed. You can pick and choose, invert, select all, then simply click on the “Enable/Disable” button to either enable or disable the selected add-ins.
  7. Once you’ve made your choices, start Revit in the normal manner. Simple and easy.

Or download it from here.

Got it to work… Thank you.

It was a conflict with a content management add-in called Avail (version, we’ve had a problem with this Add-in conflicting with Dynamo in the past.

I’ve manually disabled my user-land plugins but didn’t expect a conflict with system ones. Once IT gave the access needed to work with those it was simple. I’ll submit a dump with just the RiR and avail plug in through the link you’ve provided me previously - hopefully it helps in figuring out what that are doing that RiR doesn’t like.

Thank you for your help through this process.

Karl -

Yesterday we released a new Rhino 7 WIP that may avoid this conflict. Please update your Rhino 7 to the latest and see if you can run all the plugins. Look forward to hearing if it fixes this JSON conflict.

Was there ever resolution found for this conflict between RiR and Avail ( I’m running the latest WIP and RiR that are available at 8am Dec. 30. Avail has not responded to a service email on the subject and I would prefer to run both add-ins, but would uninstall Avail if needed to run RiR. Thanks in advance for any news.

Hi Mike,

I’ve been testing this and in a clean installation of Revit 2020.2 using the last Rhino.Inside (0.0.7403.19289) last Rhino WIP (7.0.19351.11415) and last AVAIL ( and works on my side.

I also installed AVAIL for Rhino 6.0 and used the Rhino Options plugin dialog to install AVAIL manually in Rhino 7.0 WIP.

AVAIL seems to work on Rhino 7.0 WIP standalone as well…

…but not when loaded at the same time in Revit and Rhino inside Revit.

It’s normal since AVAIL is still not supporting Rhino 7.0 WIP, the last screenshot was just a test trying to reproduce an extreme setup you may have, but not something AVAIL is supporting.

What I can say to you is the expected-supported, by AVAIL and us, setup works here.

Could you please try with the same version of each component?
Do you have any other Addon that may be interfering with Rhino.Inside?

Good news! I was able to install the latest WIP and RiR onto one of our test pcs that is running Revit 2020.2 and everything is running correctly. I’ll be deploying Revit 2020.2 in the next two weeks so this is good to see.

Where I had run into the problem was on a test VM running Revit 2019.2. RiR worked perfectly fine with a clean Revit install but I ran into the -200 error once I installed Avail as the second add-in.

Thank you for the quick response!

I was also getting the same error
“Rhino license manager initialization failed with error -200. Rhino will not run”
I did have Avail also; however, I just uninstalled the avail Revit addin and I still get teh error. Revit crashes dead when clicking ‘OK’
the RiR downloads and the Rhino WIP were downloaded as of today’s version

should I go through teh same debugging as above or is there something known to address this?

Hey @ian.atkins
The license error happens usually due to a DLL conflict with other Revit addons. Please take a look at the post below. It’d be great if you can isolate the addon that causes the conflict

Hey @eirannejad thanks for the reply. Ironically In a sort of coicidinetal twist, I took all my addins out and added them one by one. Turns out it was pyRevit that was creating the issue! I haven’t solved getting to work together yet, maybe I’m using an older pyRevit.

But at least I can get Rhino Inside working

Yes there was a conflict between pyRevit and Rhino.Inside.Revit at some point. The issue has been resolved AFAIK so try using the latest pyRevit version and let me know if you still see the issue.