Loading a large assembly results in a LISP error

The 3d models that my organization manage almost all belong to a top-level facility assembly in CED all stored in Manager Server of course. The top-level assembly is organized by rooms and the top-level assembly of each room is in a container. The vast majority of the time we are loading just sub-assemblies of the local area that we are interested in when loading from the server to CED Modeling. Occasionally we do need to load the top-level assembly when creating facility layout images for example.

Over the 30+ years that we have been using CED (ME30->CoCreate->CED) the top level assembly has gotten quite large. Previously the assembly would take days to load from Manager Server but would eventually finish. Modeling performed pretty well once the load was complete.

Recent attempts to load our top-level assembly have been unsuccessful. Most recently the load failed after chugging away for 10 days. The error thrown was “LISP error: Cannot open the file” followed by a file name in a local temp directory. The directory existed but the file in question was not there.

I have tried multiple load methods including loading all the top-level assembly at once and by loading the top-level assembly as structure only and then individually full loading containers. Nothing has worked!

The workstations we are using are quite capable (Win11 Enterprise, 256gb memory, 2tb SSDs, 2.50GHz 24 core 48 thread Xeon processor, high-end NVIDIA gpu) however CED does not seem to take advantage of the resources during the load from Manager Server process. It just chugs along using ~2% of the cpu (one thread) before eventually failing. 

Any tips on getting our top-level assembly to successfully load? Is there a way to unlock the full capability of these workstations while loading from Manager Server to CED?