Hi @slacy
Sorry to hear that the fixes, updates did not help. Did you go through all the recommendations?
Most of these errors have been linked to the installation process and incomplete download.
It could also be due to the fact that certain Third-party applications, Windows services and processes,
antivirus, firewall, and network settings may be causing Autodesk applications to interact with the OS in
an unexpected manner.
Can you try installing the material libraries again and reinstall Revit through the Autodesk Virtual Agent
Please see this post on Revit 2018 due to errors in installing material library.
See HERE to reinstall material libraries.
Can you send a screenshot of your error message and a journal file to troubleshoot?
Does the error occur during the material editing process? Have you loaded new textures files recently?
Did this error occur before in other versions?
How was Revit 2018 functioning otherwise?
Let us know and we are glad to help!
Please post to the Installation and Licensing forum if you have specific questions regarding installation.
Best Regards,