Anyone know how to prevent this crashing?

[SoggyWontonz]

So, my server will have moments where all NPCs/Props/etc will just disappear yet we can still see the shadows of them, they'll come back, and it'll flicker, then 90% of the server's players gmod's will crash/

Anyone know a fix?

[roastchicken]

I'm no expert, but the first place to look would be your server's specs. If you're running a VPS then you should be able to find this quite easily. If you're on a Garry's Mod host, then you might have to submit a ticket asking for the specs.

Do you have a lot of NPCs and props? What is your max playercount? How many people are on the server when it usually crashes?

It could be completely unrelated to serverside lag, but I think that's the most likely culprit.

[SoggyWontonz]

We use a lot of NPCs when it crashes, but sometimes we will have more than usual and it doesn't crash

[roastchicken]

How many NPCs? What are your server specs?

[blinkenn]

So, my server will have moments where all NPCs/Props/etc will just disappear yet we can still see the shadows of them, they'll come back, and it'll flicker, then 90% of the server's players gmod's will crash/

Anyone know a fix?

https://facepunch.com/showthread.php?t=1508517

Try to lower the amount of entities you have being ran on the client, The crashes is the client having more entities than the engine can hold.

I would recommend getting iNPC(https://steamcommunity.com/sharedfiles/filedetails/?id=632126111) for lowering NPC entities, but it isn't a perm fix.