Sony PCS-XG80 Operating Instructions Manual page 251

Symptom Cause
Still pictures or the The write-protect tab on the
Phone Book cannot "Memory Stick" is set to LOCK.
be saved to the
The "Memory Stick" has already
"Memory Stick."
been recorded to full capacity.
Solution
Release the lock (page 264).
Use another "Memory Stick."
Troubleshooting
251