Failure to "lock index buffer"?

[Tanuki]

So every time I try to get into S1, and this only happens for S1, my screen freezes for about fives minutes on the "Retrieving server info" part. Then gmod closes and it tells me that "buffer index" failed to lock. I really have no idea what's going on, or why this only happens on S1. I tried restarting steam, re-installing GMOD, defragging and validating. If anyone has an idea, please let me know. I wanna get back to my RPs.