Revit and Dynamo have independent development cycles, and Dynamo’s smaller codebase and functionality allows for faster changes and more rapid delivery. This means that sometimes there are public releases of Dynamo that are more recent than the versions that ship with Revit or other products. Dynamo installers will not replace a newer version of Dynamo with an older version, and so conflicts may arise. The recently released Revit 2018 ships with Dynamo 1.2.2 and some users have already installed Dynamo 1.3 independently, so you may need to make a couple adjustments.
If you have never installed Dynamo independently of a Revit installer, then just go ahead with your installation, but if you are an early adopter and have pre-release or very recent Dynamo installations on your system, then there are few thing which you should know before installing Revit 2018. Check in Windows “Programs and Features” if you aren’t sure what version you have.
Do you have Dynamo 1.0 – 1.2.1 installed on your system?
If you have any of the above version installed on your system, then you can install Revit-2018 without uninstalling any of your Dynamo Version, your current Dynamo will upgrade to Dynamo 1.2.2.
Do you have a Daily Build (recent examples are 1.2.3) installed on your system?
Daily Builds should be treated like any other beta or pre-release installs and should be completely uninstalled before proceeding
Choice 2: Install Revit-2018 without uninstalling your current Dynamo. Once you finish installing Revit-2018 you will get an error on final installation page something like this
you can ignore this failure and go ahead with next step to make Dynamo 1.3.0 available for your Revit 2018, go to your “C:\Program Files\Dynamo\Dynamo Revit\1.3(or 1.2, depending on which version you have on your system)\DynamoAddInGenerator.exe” and run this exe by just double clicking on it. (It will pop up a command prompt and will go away immediately.)