Note the approximate coordinates from the building you removed and get the classname of it. Move to your mpmissions folder and look for the file mapgrouppos.xml.
Inside this file check all buildings with this classname and narrow down the right one by referencing to the coordinates, because they will not be 100% identically.
Delete this line, save the file and restart the server and you are done.
The stuff that spawned will be still there until you picked it up or it despawned.
But no loot will spawn furthermore.

Originally posted by Stollenwerk:

Note the approximate coordinates from the building you removed and get the classname of it. Move to your mpmissions folder and look for the file mapgrouppos.xml.
Inside this file check all buildings with this classname and narrow down the right one by referencing to the coordinates, because they will not be 100% identically.
Delete this line, save the file and restart the server and you are done.
The stuff that spawned will be still there until you picked it up or it despawned.
But no loot will spawn furthermore.

Thank you sir i will try this!

You an also generate a new mapgrouppos file. Follow the instructions on the Dayz Editor wiki. It's the same command in init.c you would use when adding new buildings. You can use it when you remove buildings too.