I have installed Version 1.5.0.1357a (x64).
I have 2 SATA Drives and 1 nvme with 5 Partitions more. So far every partition can be index but one partitions is giving the error "Access denied: Install the Everything service or run as administrator to index this volume."
Only way to index is running the everything in admin. Indexing process in admin also doesn't work. Reinstalling also doesn't help.
FYR here is the drive structure, everything is installed in C drive and the highlighted drive F can't be index others are working fine.
https://imgur.com/a/N0SPnzs