Troubleshooting Guide
A–8 www.hp.com Troubleshooting Guide
POST Error Messages
918-Front USB Not 
Connected
Front USB harness has 
been detached or 
unseated from 
motherboard.
Reconnect or replace front USB harness.
919-Multi-Bay Riser 
not Connected
Riser card has been 
removed or has not been 
reinstalled properly in the 
system.
Reinsert riser card.
921-Device in PCI 
Express slot failed to 
initialize
There is an 
incompatibility/problem 
with this device and the 
system or PCI Express 
Link could not be 
retrained to an x1.
Try rebooting the system. If the error 
reoccurs, the device may not work with 
this system
1151-Serial Port A 
Address Conflict 
Detected
Both external and 
internal serial ports are 
assigned to COM1.
1. Remove any serial port expansion 
cards.
2. Clear CMOS. (See Appendix B, 
“Password Security and Resetting 
CMOS.”)
3. Reconfigure card resources and/or 
run Computer Setup or Windows 
utilities.
1152-Serial Port B 
Address Conflict 
Detected
Both external and 
internal serial ports are 
assigned to COM2.
1. Remove any serial port expansion 
cards.
2. Clear CMOS. (See Appendix B, 
“Password Security and Resetting 
CMOS.”)
3. Reconfigure card resources and/or 
run Computer Setup or Windows 
utilities.
Numeric Codes and Text Messages (Continued)
Code/Message Probable Cause Recommended Action










