Question While installing RHEL/CentOS 7.x version with X11 DP motherboards, I found it's hanging on the screen and system asks me to report the bug with " An unknown error occurred". I checked the log and found log " AttributeError: 'NoneType' object has no attribute 'startswith'" inside. How can I pass this problem and complete OS installation?<img src=".\img-lib\27037.jpg"> Answer For those users with such failure, please ensure to clean up all metadata inside HDD, including NVMe, M.2 drives, if you have ever configured those drives with RAID group and OS stored in that particular volume. RHEL/CentOS will recognize it and will not allow for new fresh OS installation to prevent from data lost. You can use command to erase metadata, $dmraid -r -E /dev/sdx  (x is the drive mapping ID inside Linux). Or you can simply remove the RAID volume with existing OS installed inside. Then, you will be able to bypass this failure message. Was this FAQ helpful? YES      NO Enter Comments Below: Note: Your comments/feedback should be limited to this FAQ only. For technical support, please send an email to support@supermicro.com.  Enter your email address below if you'd like technical support staff to reply:  Please type the Captcha (no space) Y B Q L FAQ Stats FAQ ID Related Category / Keyword Date Posted Code 27037 Operating Systems: - Linux OS Other: - Driver 12/21/17     Print Answer