Hello all, I just recently upgraded all programs and now am currently running on the following:

13"; MacBook Pro (8 GB)
OS-X Yosemite 10.10.3
Sibelius 7.5 (7.0a Template)
Virtual Drumline 2.5. (2.5.5 Library Update)
Kontakt Player 5

I've gone through the process of updating and upgrading all software, but I hit a road block in Playback in Sib 7.5 on any score I try to work on (including Sib6 files). I've read through the ReadMe files for install on both the library update and Sib 7.5, and along with the De-Mystified download, I still haven't been able to get everything running smoothly.

I have been able to set up playback configurations in Sib 7.5 (VDL 16 Sounds, VDL 32 Sounds/Sib Essentials 16 sounds, etc.) with active instances of Kontakt Player 5 showing.  I was also able to assign the 7.0a Template to those instances of Kontakt Player.  However, when trying to play back or when inputting notes, no sound.

I tried re-doing everything (re-starting Sibelius, my computer, etc.), but then when I tried to add the VDL 2.5.5 Library in Kontakt 5, I got the error message of ";Error while writing files to disc."; I believe this could be the first source of my problem, but am not sure how to go about fixing the issue.

Any and all help is certainly appreciated!

Does VDL playback in KP5 stand alone mode?

Yes.