The root cause
This message appears when you try to open an implant planning previously designed that may contain certain implants or sleeves that had been previously selected but due to regulatory decisions are no longer available or were removed by the implant libraries manufacturer.
This could be also related to recent updates or software changes in which Implant Libraries were not downloaded properly.
Resolving missing implant library issues in Implant Studio planning
To solve this issue, go to More > Settings > Implant Studio > Implant Library look for the missing library, and download/update it. If the missing Implant Library does not appear in the list, it means that it was most likely removed and in this case, it will not be able to be selected again under any scenario.
After performing the necessary download for the missing libraries that appear in the list to try the download again, the issue should be resolved, and you should proceed to open an existing Implant Planning.