Hi everyone,

I have a large assembly originally created in SolidWorks 2025 that was converted/saved for use in SolidWorks 2023.

Current behavior:

• Assembly contains around 2000 components
• Opening the top assembly in Lightweight mode works reasonably well
• The problem starts when opening or resolving subassemblies: it can take a long time before they become usable/responsive
• Assembly Statistics do not show anything unusual (rebuild times / mates / graphics triangles seem normal)
• Performance issue mainly appears after conversion from 2025 → 2023

Things already checked:

• Assembly Statistics → looks normal
• Lightweight loading enabled
• Files are local 

Questions:

1. Is there something in converted assemblies from newer versions that can cause this behavior?
2. Could this be related to graphics data, FeatureWorks history, mates, or internal rebuild data after conversion?
3. Are there recommended steps after converting large assemblies between versions (force rebuild, save all, task scheduler, etc.)?

Any suggestions on where to investigate next would be appreciated.