BlockEdit slow to start

I feel like this has been mentioned in the past but I can’t find the topic.

When I select a block and use command BlockEdit it sometimes takes 45-60 seconds to happen. Double-click on block has same symptoms.
This seems to start happening at some indefinite point as my project file grows in size. Meaning, with a new file and new blocks: no problem. BlockEdit launches immediately. After a year or two of project development, somewhere along the way all BlockEdits take a minute (or more) to start.

Purging unused blocks doesn’t seem to do any good. If I export the blocks to a new file they work fine (blockedit is fast in the new file).

The current file saved small is 124Mb. I dunno if attaching it to this post is a good idea? I can share a dropbox link or upload to support (via: http://www.rhino3d.com/upload), whatever you prefer.

Hi Ed,
You can upload it for us using this link.
You can dropbox it and sent a link with the problem description to tech@mcneel.com.

You can put attention: Mary Fugier. Also include is this Rhino 5 32bit or 64bit? Windows 7 or 8?
What add-ons do you use? Vray? RhinoCAM?
I will be watching for your file.

Thanks for letting is know about this.
Sincerely,
Mary Fugier

Thanks Mary. I’ve uploaded it via http://www.rhino3d.com/upload

The file is “mammoth_v13 06022014.zip”, inside that is 3dm file of same name.
I’m using Rhino5 64-bit and Win 7 Pro 64-bit. Plugins are Maxwell, Grasshopper, Holomark1, Holomark2, and Paneling Tools.
The computer is a custom-built i7-2600k 3.8GHz with 32Gb ram and… a bunch of other sh*t. Let me know if you need more details.