I already Unwrapped this model When I export it as an OBJ from 3ds max into ZBrush, the model in Zbrush has no UVs. Attachment not found. When I check if the model has UVs in Zbrush, I have found out that if the "Delete UV" is greyed out, meaning there are No UVs. Attachment not found.…
Sorry, what I meant was, take the OBJ you exported from Max and re-import it into Max without going through ZBrush first. This way, If your UVs are gone it rules out ZBrush as the culprit.
I'm fresh out of ideas for the time being but it may help others if you stated what version of Max and ZBrush you are using. Each version of software comes with their own unique set of problems...
Yeah this is a long standing Zbrush bug. One I reported years ago, and no fucks were given by Pixologic. I had the issue with a model from Maya though, not Max. Really sucks to see that this is still an issue. Probably means all the other UV issues such as unwelding them at the vertex level are still there.