Lots of folks having this error, including me. What I have found is here:
https://www.grouppolicy.biz/2018/05/how-to-fix-searchocs-admx-error-after-upgrade-to-windows-1803-admx-files/
Followed the steps outlined and the issue is resolved.
One posting also referenced "the SearchOCR.ADMX file is only installed in the PolicyDefinitions folder if you have the "Windows TIFF Ifilter" option installed. If you have ever done this on an old version of windows and then copied it across to the Policy Definitions folder then this will be an old version of the file as it wont be updated using the ADMX/ADML bundel that Microsoft publishes. "
He recommended..."either 1. Delete the SearchOCR.ADMX file if you don't use any of the policy settings or 2. Install Windows TIFF Ifilter on a computer running Windows build 1603 (server or workstation) and copy that SerchOCR.ADMX file into the central store. "