“If you change the drive letter of a drive where Windows or apps are installed, apps might have trouble running or finding that drive. For this reason we suggest that you don't change the drive letter of a drive on which Windows or apps are installed. Aug 7, 2020” - That's the little advisory I mentioned. You can certainly change the drive letters. Are you still using both 1TB and 6TB boot drives?  A couple of ideas.  1. Just use the 6TB and leave the 1TB out.  Or, if both are in, you'd likely have to go into the boot menu to pick which one to boot from.  2. Wipe the 1TB drive and use it for storage. As for question #3, I'm not quite sure why you would want to do all of that.  You should be able to change drive letters with both drives in, whichever one you boot from.  If you can't change drive letters on the drive you booted from, leaving both drives in, boot from the 1TB drive, change drive letter for 6TB to something other than D, any letter that isn't used already.  Then you should be able to change 1TB drive letter to H.  Then change 6TB drive to D. Hopefully that all makes sense.  See, if you have a D drive in, and you try to change the 6TB drive to D, it won't let you change it.  Can't have 2 drives with same drive letter, even if temporary. If you're more comfortable with removing a drive to boot from the other, rather than use F12 Boot Menu, that's fine. While I've changed drive letters before, I don't know that I ever changed drive letters on the drive I booted from.  So that's my best advice.
Thanks in advance if you can help me with this question. I love my T7600.  I have had it since I bought it at the Dell Outlet in 2014.  Especially fond of the easy access components like the power supply and 8 hard drive bays. I don't have any big problems right now.  I recently successfully cloned my 500GB SSD boot drive to a 1T SSD with FSS Casper software. However, when cloning my 1T Seagate HDD to a 6T Toshiba HDD, the operation failed 3 times with an error message that the source drive may have a cabling problem. So I am trying to find a work-around for this situation.  One of the questions that no one has been able to answer for me is...  1. In the T7600, can I pull a drive out of its bay and put it into a different bay without causing a problem with the system? I do not have RAID.  I don't have to move any of the SSDs.  Just one or more of the 3.5 drives. None of the HDDs have specific Volume Labels.  Would naming them make a difference? I would be thrilled if you can answer that question - it seems simple, but I can find no reference to moving hard drives around in accessible bays perhaps because so few people have this ability. Just in case you are interested, more details... I am a cartoonist, filmmaker, graphic designer, etc. hence the need for space.  The 1T drive I am trying to clone is my D drive.  It is in drive bay 0.  It holds important active folders like MS OneDrive, and temp files like app data.   Not just stuff I have saved.  After cloning failed using a SATA to USB adaptor, I put the target drive into drive bay 3.  I had to format the drive and give it a drive letter H in order for Window 10 to see it.  Since I have received the same error message 3 times, that the problem is likely the SATA connection in Bay 0, I would like to try moving the D drive to a different bay.  I would have to remove or switch with a different drive to do that.  If that doesn't work, it probably means the problem is not the cabling to the 0 bay.  At least I will know that and start trying some other work-arounds.  My Specs:  T7600 Precision WorkstationCPU: 2 x Intel Xeon Four Core E5-2609 0 (2.4Ghz, 10M, 6.4GT/s)32GB (4x8GB) 1600MHz DDR3 ECC RDIMM1 PNY NVIDIA Quadro M4000 Graphics Card VCQM4000-PB1300W PSUWindows 10 Pro 64bitNo RAIDSamsung 860 EVO 1TB 2.5 Inch SATA III Internal SSD (MZ-76E1T0B/AM) Boot Drive num Title-type-brand-model number size GBs-Ts BUS num Drive Bay C ATA SAMSUNG SSD  860 SCSI 2.5 1T 1 5 D ATA ST1000DM003  1CH1 T SCSI 3.5 1T 4 0 G ATA ST3000DM001  1CH1 3T SCSI 3.5 3T 6 2 F ATA TOSHIBA DT01ACA2  2T SCSI 3.5 2T 5 1 M ATA  WDC WD20NPVX-00E  2T  SCSI 2.5 2T 0 4 H ATA TOSHIBA HDWR460 6T SCSI 3.5 6T 7 3
T7600 Precision Workstation drive bay question