Cannot append when using compression or encryption

Error constant SQLE_UNLOAD_CANNOT_APPEND
ODBC 2 State ERROR
ODBC 3 State ERROR
Severity 16
SQLCODE –1187
SQLSTATE WL012
Sybase error code 13328
Probable cause

The UNLOAD statement cannot append to a file when using compression or encryption. Either the compressed or encrypted keywords were specified, or the file being appended to is compressed or encrypted.