external reference - Big headache!!!

The x-ref stuff is getting like more than a headache for me. I use 09 Autocad. I do shop drawings for a sheet metal company. Most of the time I get mechanical plans with lights and proposed ceiling plans as an X-ref. The problem is that sometimes the lights and proposed ceiling plan gets erased on my final ductwork drawing. I can't see walls, lights, doors, room number, etc. Does anybody know what could be the problem here???

Assuming that those numbers etc. DO exist, go back into the XREF and turn ON the layer to which they supposedly exist upon. Then you got em'.

Wm.

Maybe even cleaning out the x-ref'd dwg might help (purge/audit/reg apps etc) if you haven't already done so

What do you mean it gets erased? Are you saying it's there one minute and then gone the next? Are you accidentally selecting it and deleting it, or maybe you're Freezing it? A little more information about what exactly is happening would be helpful.

If the X-ref file is getting deleated the bak file may still be around but as Cad64 says more info may be needed.

ensure the baseboint of both drawings is at 0,0,0 or known. Also before either xrefs are saved the ucs must be the same before bring it. If one has a section cut on it and ucs is at view, it will come in all over the place! dont dorget to thaw all the layers too!