For VEGAS Pro 14 and later you need to change the namespace in the script. Change this line:

import Sony.Vegas; 

...to this:

import ScriptPortal.Vegas; 

Nick - im already discovered this, because scripts don't want to work completely :)

wwaag - nice, but this is not a solution for professional program, when user must "repair" bug few times per day. Im still hope, that new Vegas owners can solve this bug once and for all :)

This is an o-o-o-old bug. To fix it, Vegas programmers have to figure out what code could be the cause of it. To do this, they need to install multiple scripts, extensions, use them daily, and watch the toolbar :)

BTW, Vegasaur 2.6+ can detect disappeared icons on the toolbar and automatically restore them. Not a bug fix, but this works 99% of the time.

I have almost pure vegas without extensions (only newblue/mercali from magix last promo) and only 5 script on toolbar, which only 3 with icons. Default icons "parchment" don't disappear.

For me, at least, it's always been associated with doing something in an external program while editing.  In particular, doing something in Photoshop could/would almost certainly make the icons disappear--not every time, but enough to make it a real pain.  Another annoyance is that files created in photoshop and brought into Vegas cannot be deleted from within Vegas.  E.g. select an event in the project media window, right click and choose remove from the project and delete files.  You can remove a PSD from the project, but not delete that file, event though programs such as Unlocker show that Vegas does not have a handle on it. 

You've probably done this already, but if not, the best use of altarvic's script is to assign it to a keyboard command--I use F4.

This still exists in VP15 build 216. malowz noted that a simple way to reproduce is disconnect the video cable from a second monitor. I just tried that and it happened for me too, even with Vegasaur running.

It's important to note that this is a different issue from the one whereby installing plugins or scripts causes buttons on customized toolbar to get replaced (discussed here and here), which also still exists in VP15 build 216.

So, this is the reliable way to reproduce this bug (at last!) - I also could reproduce it.
I hope that VEGAS team will fix it soon.

Nick, Vegasaur does not fix this bug, but it can detect that icons were unloaded from memory (to be more precise - from toolbar's image list - this information for VEGAS developers) and load them again. It performs a check when switching from another application.

hi! i believe I'm having this problem in Movie Studio 17 Plat--any idea how to reliably fix it? I'm attaching a picture here to show what I mean so you can compare to the original concern:

@Daniel-Hahn search nahimic or "sonic studio" on this forum.

Generally, please start a "New Post" for your specific issue.

hi! i believe I'm having this problem in Movie Studio 17 Plat--any idea how to reliably fix it? I'm attaching a picture here to show what I mean so you can compare to the original concern:

This is definitely not the same problem. However, from your screenshot you can't tell what's "missing" without more information.