1. Recently, I wanted to clone a 500GB external hard drive using USB2. 2. OS was XP/SP1. 3. After switching on and off the new drive several times, it was recognized as a local drive. 4. Cloned the HD using Acronis True Image Home. 5. Now the computers (tried with 2 computers at different times) recognize only one external (e.g. M:,N:,O:,P: or U:,V:,W:,X, but not both at the same time. 6. The icon 'Unplug or Eject Hardware' in the tray also vanishes when I fiddle with the power switches. The icon comes back only after I I remove one ehd and then fiddle with the switch of the other ehd. The external hard drives are connected to separate power sources. 7. However, the computers can recognize one 500GB and one 160GB drives at the same time(e.g. M:,N:,O:,P: or U:,V:,W:,X:,Y:,Z in addition to 2 normal hard drives (C:,D:,E:,F:,G:/200GB and H:,I:,J:,K:,L:/250GB). 8. Does anyone know about an inherent limitation of the OS or USB2? Shall be grateful for a solution, or at least for an explanation.
This is all a bit confusing. List all the hard drives you have here, and whether they're internal or external, along with which drive letter they're usually given.
Above thread expanded with clear references to drives and drive designantions: 1. Recently, I wanted to clone one 500GB external hard drive to another 500GB external hard drive using USB2. 2. OS was XP/SP1. 3. After switching on and off the new external drive several times, it was recognized as a local drive (My Computer display). 4. Cloned the external HD using 'Acronis True Image Home'. External drive designations M:,N:,O:,P: and U:,V:,W:,X:. 5. Now, after rebooting, the computers (tried with 2 computers at different times) recognize only one external (e.g. M:,N:,O:,P: or U:,V:,W:,X, but not both (500GB external drives) at the same time. 2 normal (internal) hard drives (C:,D:,E:,F:,G:/200GB and H:,I:,J:,K:,L:/250GB) are always present. 6. The icon 'Unplug or Eject Hardware' in the tray also vanishes when I fiddle with the power switches of the external hard drives. The icon comes back only after I remove one ehd and then fiddle with the switch of the other ehd. The external hard drives are connected to two separate power sources. So voltage drop etc. can not be the problem, 7. Alternatively, the computers can recognize two external (500GB and 160GB) hard drives at the same time (e.g. M:,N:,O:,P: and U:,V:,W:,X:,Y:,Z in addition to 2 normal(internal) hard drives (C:,D:,E:,F:,G:/200GB and H:,I:,J:,K:,L:/250GB). [This was an alternative trial arrangement]. 8. Does anyone know about an inherent size limitation of the OS or USB2? Shall be grateful for a solution, or at least for an explanation.
Without installing SP2, I believe that the size limit seen, is 138GB, or something like that. There was some software or registry hack that could get it to read larger drives, but I instaled SP2 instead.
Are you referring to the 'EnableBigLba' entry to the registry? It is already enabled, and the computer recognizes 500GB and more for internal hard disks. Even for external USB hard drives 500GB + 160GB are recognized, but 2x 500GB as external drives behave peculiarly. Connect 3 large external drives, and the OS does not know which is which.
