Acronis True Image 2016, build 6027, on Windows 8.1 Pro x64, on a Core i7-3770K @ 5.0 GHz. Backup disk is a 2TB hdd (spin disk). I have a 150 GB backup .tib on it which was made using medium compression and contains 3 partitions (16+64+350 GB). Mounting the 350GB partition inside it as a drive letter takes almost 15 minutes all the while thrashing the backup disk. It looks like it reads the whole file before mounting (why?) since I can see the process reading from the hdd at about 80 MB/s using Process Hacker. I made a backup using Macrium Reflect of the exact same partitions and placed the backup on the same hdd. Macrium Reflect mounts it as a drive letter in 1 second. Same with AX64 Flashback. So the problem is with Acronis, not with my disks or system. Any clues? Anyone else experiencing this? Can anything be done? EDIT: Interestingly, if I double click the .tib then I can get into it and to the partitions almost instantly (1 second). I need to mount it as a letter as I'm using other tools to read from the backup ... I can't use the explorer-like interface that opens when I double click the .tib.