Creo 6.0 losing merge references

If you were attempting to open a support call with PTC you did not. You have posted to the Creo user community, if you want to open a call with support you will need to resubmit the request.

If you intended to get help here in the community, you will need to provide more information to allow someone to help.

When we moved from Creo 3 to Creo 4, we had a lot of merge failures also. For us, this was specifically related to merge parts there were made from a welded assy where after we created the merge part in the assy, we would suppress the merge part so it wouldn't show up in the BOM or the weight of the weld assy. Prior to creo 4, this process would only stop the automatic update of the merge part but wouldn't specifically fail the merge features in the merge part. Once updated to Creo 4, every merge part that had been suppressed would show RED in the model tree and upon regeneration, it was likely the part would completely fail and not produce any solid geometry from the merge features.

Our solution was to NOT suppress and/or resume the merge part in the weld assy and we started finding other ways to control the merge part within a weld assy other than surpressing them.

Obviously, due to lack of info in the original post, this may be a completely wrong direction.