My Passport Essential and Ultra compatibility?

I have 3 My Passport, one Ultra and 2 Essential bought in different years. I use them in a portable PC running Windows 7. When I plug the ultra one first, Essentials pass password request but system file is not recognized. I have to reboot the portable an then they are recognized and perfectly usable. Supposedly, WD soft. drivers are up to date. Hints?

Hello ManuelRG, welcome to the Community. You might have a signature collision problem, see if the following link helps.

Only one drive is seen when connecting two WD external drives of the same size to a Windows 7 or Windows 8 PC

You can also try running a DLG test.

How to test a drive for problems using Data Lifeguard Diagnostics for Windows 

I’ve been doing some exhaustive testing after disabling password security to prevent possible interferences between different versions of security and Unlocker.exe, with the following results:

  1. I can connect all three units together and get them fully operative if and only if the last one I connect is the My Passport Ultra.
  2. If I connect the Ultra unit in second term, a third one I connect is not usable (*)
  3. Once the Ultra unit has been connected in any moment, only one unit can be connected at any time. May be anyone, but only one. A second or third unit connected simultaneously result(s) as not usable, including the Ultra one (*)
  4. Rebooting reset this situation to case 1.

(*) Unusable units appears in diskmgmt.msc as connected, with NTFS primary partition and correct (disk label is also visible) but without unit letter assigned; no mark of warning as in signature collision. In WD Smartware, they appears as partitions without writable area.

I have yet to test differences with password set.

PS.:

Technical details, as identified by WD Smartware:

Unit 1: Product Id.: 0730, Essential, Firmware 1016, 1 TB

Unit 2: Product Id.: 07A2, (no “second name” after “My Passport”), Firmware 1042, 1 TB

Unit 3: Product Id.: 0820, Ultra, Firmware 1007, 2 TB