X_DEV_STATE_UNWRITABLE
Means
x dev cannot claim its state directory
Typical cause
the state directory could not be created, written, or hard-linked into, so x dev cannot take its lock — a read-only checkout, a .x/ this user may not write, or a filesystem without hard links
Fix
ls -ld .x — make it writable by this user, on a filesystem that supports hard links, then re-run x dev