Definitions of alerts returned by credit bureaus:

Bureau Alert Type Sample Alert Message Explanation
Trans Union TU HAWKHAWK available and clearNotification that HAWK was run on this request. One of several possible notification messages.
TU HAWKHawk system is temporarily unavailableHAWK may return one of several messages indicating partial or no availability.
TU HAWKInput current address is a mail receiving/forwarding serviceHAWK found possible fraud associated with this name, address, SSN, or phone#. May be "Input" or "File", "current" or "previous".
TU LOOKLOOK Product was deliveredNotification that directory lookup was included on this request. Also applies to alert types "TU LOSS ALERT" and "TU PHONE APEND". Append is misspelled - this is a known issue.
TU LOOKSubscriber code not authorized to request the LOOK productNotification. Also applies to alert types "TU LOSS ALERT" and "TU PHONE APEND". Append is misspelled - this is a known issue.
TU EMPIRICA ScoreEMPIRICA score product was deliveredOne of many score model alerts that may be returned.
Edit Alert(various)Misc edit alert returned by TU
TU Processing ErrorPassword missing/invalid. Contact your local bureau if assistance is needed.The inquiry was not formatted properly or did not contain valid login information.
Address AlertMismatch - input does not match fileMisc data alert returned by TU. Alert message may say "Invalid Information" instead. Also applies to alert types "SSN Alert", "Zip code Alert", "Surname Alert", "Recorded inquiries Alert", and "Trans Alert".
Equifax SAFESCANSAFESCANNED: Your inquiry has gone through our SAFESCAN data base.Notification that SAFESCAN was run on this request.
SAFESCANSSN: 999-99-9999 Verified: 2000 WA Age: 25 Issued: 1975 CASAFESCAN reported year and state verified and issued.
SAFESCANSAFESCAN Warning: Social Security number has never been issued by the Social Security Administration.SAFESCAN found possible fraud associated with this name, address, SSN, or phone#.
NOHITEquifax returned a No-Hit on this inquiryBureau does not have any information on the SSN you entered.
EFX Format ErrorCustomer Number/Security Code Invalid (DIAL)The inquiry was not formatted properly or did not contain valid login information.
EFX Validity ErrorInvalid Customer NumberThe inquiry contained invalid subscriber or applicant information.
EFX Processing ErrorNo Record Found - Check input for accuracy, if social available try DTECThe bureau had a problem processing the inquiry, usually due to invalid inquiry information.
EFX Bureau ErrorInvalid file format near: ...The file returned by the bureau contains an invalid segment or is in an unrecognizable format. The alert message will usually contain a portion of the file near where the invalid segment was found.
Experian XPN FACS+(various)Fraud alert message returned by Experian FACS+.
InformativeInvalid security passwordThe inquiry was not formatted properly or did not contain valid login information. One of a large number of possible alert messages. Also applies to alert types "Correct and/or resubmit", "Report condition or database problem", and "Suspend".
XPN Error(various)The file returned by the bureau contains an invalid segment or is in an unrecognizable format. The alert message will usually contain a portion of the file near where the invalid segment was found.