I selected all in distribution select, archive extraction: base.txz kernel.txz base-dbg.txz kernel-dbg.txz lib32-dbg.txz lib32.txz ports.txz src.txz tests.txz Speculation: it was supposed to be either lib32-dbg or lib32 selected, not both. FIX (based on speculation): Make no more than one selectable in group of lib32-dbg, lib32, yet should still be possible to uncheck.
Could not reproduce. Didn't specify: before and now filesystem choice is UFS. Maybe it had something to do with the fact one ftp mirror (latvia) failed to download some -dbg.txz etc. errored out yet perhaps still extracted some, then I cancelled restarted install that maybe somehow didn't reformat the storage to clean state. Needs more people stumbling upon this error to narrow down the cause.
What version and arch of FreeBSD?
*** This bug has been marked as a duplicate of bug 266987 ***
We've seen this exact error downstream in CheriBSD when restarting the installer. Note that lib32 and lib32-dbg are coinstallable (in fact all distributions are). The latter contains debug files that sit alongside, and for, the former.