From: Jason Smith (
Date: Wed Dec 16 2020 - 19:35:18 CST


just installed this today (vmd194a50win64-SetupV3) and have been unable to open large trajectories :(. BTW I am very very excited to be able to address larger amounts of memory on a 64-bit version. Thank You!

Through some trial and error it seems like the problem lies in the file size, not whether the file fits in memory. For e.g.

977 MB file in a50 opens, a 2.9 GB does not (28 GB free memory, 32 installed). For 1.9.3 in the past I always found it would crash when trying to use more than around 1.1 - 1.3 GB of memory.

What's more is that I can't use frame striding to get around it. In 1.9.3 and 4a48 I can open up my 100 GB files using striding, but I can't open the 2.9 GB in a50 using striding.

I also repeatedly opened a 750 MB DCD in a50 until task manager indicated 4.5 GB usage by VMD, so not a 32-bit memory limit. I also tried to open the files from HDD vs NVME in case it was a hardware issue.

The error given is:

dcdplugin) Could not access file 'E:/temp/6yb7_NPT_Production-2.dcd'.
ERROR) Could not read file E:/temp/6yb7_NPT_Production-2.dcd


Jason Smith
Post-Doctoral Fellow
Robert N. Young Lab, Simon Fraser University
8888 University Drive, Burnaby, BC, V5A-1S6