Steve...
I think I see your pain now. I assumed you were a Vault user.
Sorry...I don't have much expertise outside of not using Vault.
I've always preached that whether you have one user or 100's using Inventor....Vault is almost a necessity.
Even for my non-work files I use Vault. If it's not for the file management, it's for the search capabilities.
But, that's a whole other conversation.
I know it's not going to help your situation.
So...just for comparison....
Vault tends to manage this for us (40+ Inv users) and let's us know exactly where we are at and where others are at.
I have a 20k piece file open right now and did a refresh which tells me exactly where all the file version are at and how they compare to what Vault has. It took seconds.
Next, I cleared my workspace and got the entire 20K component file from Vault and opened it. This would be the worse case scenario. It would be like grabbing every file and updating all assemblies including the top level assembly.
It opened in 3 min, 29 sec. using INV2019.
Next, I reopened the same top level again from Vault..... Since, no files changed it opened the same assembly in just over a minute. It really didn't have to update or grab any files. 2 min , 4 sec.
Now, if only a few assemblies or parts were out of date by one or more users, Vault will only download the files that have been updated or not in the original assembly on my workspace. Normally a 5 to 30 seconds..... all depends on the number of files that change or need to be brought down from Vault.
I know it doesn't really help your situation...but at least it might give you a comparison in regards to not using Vault and using it.
Good Luck,
Steve H.
Steve Hilvers
Inventor Certified User / Vault Professional Influencer