Hi Jack,
To see more information from which remote system is locking your system enable the following parameter:
rfc/signon_error_log
rfc/signon_error_log
Parameter description :
Value 0 = Inactive
1 = Short dump active
2 = Short dump activae and trace output in developer trace
files (dev_w*)
-1 = No short dump, but an ABAP message and trace output in
developer trace files (dev_w*)
If you set the value of the profile parameter to 0 (that is,
rfc/signon_error_log = 0), no ABAP short dump is written, but an entry
is created in the syslog.
If you set the value of the profile parameter to 1 (that is,rfc/signon_error_log = 1), the system outputs the short dump
"CALL_FUNCTION_SIGNON_REJECTED" every time a logon error occurs. You can analyze the content of the dump using the ABAP short dump analysis
transaction (Transaction ST22).
If you set the value of the profile parameter to -1 (that is,rfc/signon_error_log = -1), an ABAP message is generated instead of the
short dump. This is the default setting.
Please note this will create short dumps in solman and if you have many rfc's might create a few but this will give you hostname of calling system to lock user. You can activate and deactivate via RZ11.
Kind Regards,
Johan