Libraries Un-compiled libraries containing many components can be slow to load. This can cause the program to appear frozen for several seconds when the Libraries panel is accessed. Large libraries are more efficiently accessed if they are compiled into an Integrated Library. These are in a compiled, compressed format, and will load much more quickly into the Libraries panel. For more information on creating an Integrated Library, refer to this document: https://www.altium.com/documentation/altium-designer/working-with-integrated-libraries-ad Remove installed libraries that are not being used in the current project. Extra libraries will take up extra memory, so removing these may improve performance. To remove installed libraries, open the Available File-based Libraries dialog from the Components panel by clicking the "hamburger" button in the upper right corner of the Components panel, and choosing the File-based Libraries Preferences from the associated menu. The Available Libraries dialog will appear. Remove any unnecessary libraries from the Installed tab. If a library is required in the future, it can be reinstalled in the same dialog. For more information on the Available File-based Libraries dialog, refer to this document: https://www.altium.com/documentation/altium-designer/integratedlibrary-dlg-addremovelibrariesformavailable-file-based-libraries-ad
Loading 3D body objects There is a known issue with Malwarebytes as described in this forum post: https://forum.live.altium.com/#posts/238134/728145 In the post, there's a screen shot that shows you can add C:\Program Files\Altium\AD[version#]\AltiumMS.exe to the Allow list to resolve this issue, but you can just add C:\Program Files\Altium. One of our product specialists also noticed, "…without any Malwarebytes exception, the PCB document was exceedingly slow to load, and 3D Body object did not show in the PCB document in 3D Layout Mode. Adding an exception improved performance and resulted in the 3D Body objects being correctly displayed."