topic Re: Fixing corrupt VI in LabVIEW

Fixing corrupt VI

Klox — Tue, 17 Jul 2012 18:38:41 GMT

Classic noob case of not doing autobackups for some small project. Usually I work straight from Dropbox, but the last two weeks I was on a new machine and just didn't make obviously (now) small effort to set it up. Anyway, I've seen a few posts from last year where a couple of individuals magically fixed the header/footer of the VI in a hex editor. I've tried browsing it, and doing random stuff (replacing first few bits from a new file, etc.). I'm just hoping for a bit of that same magic before starting the rebuild.

Specifically loading the VI gives:

"LabVIEW: File is not a resource file. The file 'ManualControl.vi' could not be loaded."

Developed in Labview 2011 64-bit. I'm with a university, but I don't think there is free support from NI available anymore for us academics. Thanks for your time.

Re: Fixing corrupt VI

odessy27 — Tue, 17 Jul 2012 22:43:23 GMT

I was in similar situation few days ago, almost lost my 3 months worth of work. Only thing that saved me was my laptop that was closed at home and did not synch up to the currupted version yet. Had to go home, disable wifi and retrieve the earlier version. I would also like to know if there is a way to retrieve these vi.

Re: Fixing corrupt VI

Klox — Tue, 17 Jul 2012 22:48:04 GMT

If you're using Dropbox you can go back to old editions of a file. See https://www.dropbox.com/help/11/en. I don't know how this service is free 🙂

Re: Fixing corrupt VI

SteveChandler — Tue, 17 Jul 2012 22:54:32 GMT

Source control, source control, source control.. Subversion is free and very easy to use.

Re: Fixing corrupt VI

Dominik-E2 — Wed, 18 Jul 2012 17:07:56 GMT

Unfortunately, as this link shows, there is no official way to recover a corrupted VI. As other users have mentioned, we recommend backing up your VIs frequently so if a problem like this occurs you don’t lose all of your work. Sorry we can’t help you out.

Re: Fixing corrupt VI

Spaz — Mon, 01 Apr 2013 22:31:05 GMT

Yeah, well it's pretty annoying. I was working on a small utility, hadn't saved it since opening it today, and both the source file and the autosave is corrupt. That may be unfortunate, but it is also UNRELIABLE.

Re: Fixing corrupt VI

billko — Mon, 01 Apr 2013 22:47:45 GMT

@Spaz wrote:

Yeah, well it's pretty annoying. I was working on a small utility, hadn't saved it since opening it today, and both the source file and the autosave is corrupt. That may be unfortunate, but it is also UNRELIABLE.

I've had it where autosave corrupted the VI and had to go back to the original file, erasing a few hours of work. In that case, version control would not have helped because I am not in the habit of commiting my changes every few minutes. (What i sweird is that I save often, and it made me go back to the original that was a few saves ago.)

Re: Fixing corrupt VI

Darin.K — Mon, 01 Apr 2013 23:07:13 GMT

Early Christmas present.

Edit: Just saw that the commenter was not the OP. Oh well, very late Christmas present.

Re: Fixing corrupt VI

Spaz — Tue, 02 Apr 2013 18:44:14 GMT

The newest version that I have is 2010. I still use 7.1 the most. (RE: http://forums.ni.com/t5/LabVIEW/Why-I-prefer-using-LV-7-1-Sort-of-like-why-I-keep-using-XP/m-p/1112416)

Althiough I got around my problem, I would be very interested in seeing any other approaches if that's the subject of your VI. Seems small... a screen shot of the BD would suffice.

Re: Fixing corrupt VI

Darin.K — Tue, 02 Apr 2013 18:54:33 GMT

I just posted a fixed version of the original VI, without checking the date of course. I have a little utility which tries a few things to fix or otherwise retrieve data from corrupted VIs and LLBs and this one happened to have fixable damage.

Too bad I was asleep at the switch when the original post happened.

Edit: Just got the solution and Kudos from the OP. Excellent. I like it when my spelunking into the depths of LV has beneficial side effects. Better late than never it seems.

Re: Fixing corrupt VI

Spaz — Tue, 02 Apr 2013 18:55:44 GMT

I was able to recover mine, so I thought I would share. This will not work in all cases like the poster submitted in http://forums.ni.com/t5/LabVIEW/vi-corrupt/td-p/1256628 where there was a resultant 'Generic Error' dialog, but seems to work on the type where LV just goes 'poof' when you try to open the front panel of the corrupted VI. Maybe like Mike Porter's commenting about in LV2011 here: http://forums.ni.com/t5/LabVIEW/is-there-a-way-to-recover-a-damaged-VI/m-p/1863387

I was working in the block diagram of a simple, single VI in LV2010, just cleaning up some wires, when LV went away w/o any dialog box or warning. I found the autosaved copy and my original from the start of the day corrupted. Any attempt at reopening either VI also resulted in LV disappearing without leave. I also wasn't able to load it via the VIServer and then programatically pop up the BD...

This was my work around:

I opened a new VI in LV. On its blank BD, I selected to add the corrupted VI from the 'Select a VI...' entry at the bottom of the Functions palette. To my surprise it let me add the VI. Its icon was visible, but any attempt to access the front panel caused 2010 to puke. I then decided to use the 'Find and Replace' search to look for a function ('Add') that I knew was in the corrupted VI's BD. The BD of the corrupted VI popped up intact when I double clicked a result in the 'Find' dialog. I was then able to cut and paste chunks of the BD to a new VI and save it.

Hope this comes in handy for someone.

Re: Fixing corrupt VI

Klox — Tue, 02 Apr 2013 18:55:49 GMT

Very impressive, thanks! I already rebuilt this some months ago, but any chance of sharing your secret magic wand? 🙂

Re: Fixing corrupt VI

Darin.K — Tue, 02 Apr 2013 19:06:09 GMT

The working technique in this case was to progressively replace bytes in the beginning of the file with corresponding bytes from a new blank VI. Looking at the results, it appears 16 bytes was the magic number in this case.

Re: Fixing corrupt VI

Klox — Tue, 02 Apr 2013 19:23:19 GMT

Thanks! I wish I could have marked this one as the solution now. I just did a manual adjustment with notepad++ and it worked for me too. I can't remember everything I tried, but I definitely tried doing some hex adjustments. I guess I didn't take it far enough.

Cheers!

edit It looks like I could change the solution 🙂

Re: Fixing corrupt VI

T999 — Fri, 02 Jul 2021 21:46:18 GMT

I had the same problem...

I opened the files in Vim and noted that at the end, "a.vi" was missing when i compared it to a file saved with the same name...i added those and it, magically, came back to life!!

from this...

to this....

literally, magic...?

Re: Fixing corrupt VI

billko — Sat, 03 Jul 2021 03:06:08 GMT

No. Literally, "binary edit".

Re: Fixing corrupt VI

T999 — Tue, 06 Jul 2021 18:19:06 GMT

I was just pointing out my magical luck 😉

not knowing what got corrupted and editing those bits seemed a bit too easy to believe 😛

but I guess one could say, "literally, moving electrons around..."

hmmm...does that make me an "electron whisperer?"