When DBF/CDX files reside on a network share (common in legacy systems), network latency or partial SMB protocol mismatches can cause file handles to drop momentarily. An exclusive open attempt during a micro-outage yields error 0x3.
When this error occurs, users may notice:
If the table is part of a Database Container (.DBC):
OPEN DATABASE YourDatabase
VALIDATE DATABASE RECOVER
For free tables:
USE YourTable.DBF EXCLUSIVE
VALIDATE TABLE