I'm not one of the people who made the bone merger mod, nor I'm the guy that reuploaded it, but It seems like it's time for me to finally say something.

This Bone Merger tool is outdated since the day it was released on the workshop, all of the bugs that have been discussed in this tab is because of the outdated lua script within the addon itself. While in some cases it works, but in most cases, it doesn't, this tool didn't age well at all because it was a simple reupload and it's originally from Gmod 12.

In order to finally put this situation to an end, It is safe to say that Bone Merger should be offcially considered outdated.

There is a tool that does the same job, called "Easy Bonemerge Tool", as the name suggests, it is pretty easy to use on it's own and it has A LOT more features than Bone Merger.
"example: you can delete specific bone-merged items without deleting all of it"

Please consider unsubscribing to this addon and focus on subscribing to Easy Bonemerge Tool instead, you won't have to face certain bugs on your first attempt, as Easy Bonemerge Tool is up to date.

Easy Bonemerge Tool:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=170917418&searchtext=East+Bonemerge+Tool