We've seen this happen before.
To get rid of the missing reference go to "Options\Zone Categories" and select one of your active Zone Stamps. Once you save the file you shouldn't receive the message anymore.
David Larrew, AIA, GDLA, GSRC
Architectural Technology Specialist
a r c h i S O L U T I O N S
WIN7-10/ OSX 10.15.7
AC 5.1-25 USA
