Receiving 'insufficient disk space to perform operation' when applying signature

User is receiving the error 'insufficient disk space to perform operation' when attempting to apply a signature to a document. After clicking 'okay', the signature appears, but will not apply to the document. Completely closing Adobe allows signatures to work, but only briefly. Plenty of RAM / storage on device.

There's nothing in the signature / initial field when opening Fill and Sign options, so nothing to remove (that was the listed resolution on another post).

Seeking assistance getting signatures working without issue for the end-user.

Thank you,