Unable to open a Fritzing file on my Mac

Steps I took that resulted in the problem:

…I was working on a PCB for a few hours, I had everything saved already, been working on it for some days, and then all of a sudden the file crashed and closed on me, when I went to open the file again, I get this message, when it’s loading and reaches 49% loaded, this comes up… " Unable to open ‘/Users/jasonberger/Desktop/BlenderBoxPCB1.fzz’:zip.open(): %d " …This is a bummer, hours of work lost if I can’t open this file again…Please help!

What I expected should have happened instead:

…I expected to keep on working, but my project crashed.

My version of Fritzing and my operating system:

…I’m using MacOS Mojave Version 10.14.6…The last Fritzing I downloaded was on December 1st 2019.

Please also attach any files that help explaining this problem

From the described symptoms, the initial crash corrupted the zip file some way. An easy test is to try to unzip the fzz file. If that fails, it is not (any longer) a Fritzing error causing it to not load. If it can be successfully unziped, additional options are possible.

Hi, how do I publish it exactly?

Hi thanks for the reply…How exactly do I try to unzip the file on a Mac?..I was able to compress the file and then unzipped the compressed file…Is that what you mean, or is there another way?

fzz files are actually zip files (with specific Fritzing content). Some systems and tools will let you just unzip it directly. Otherwise, rename it to change the .fzz to .zip, then unzip. Test the process first with a .fzz that is working, to make sure any problems are due to the specific file, not the steps used to extract the content. The extract should create a folder with a .fz file, plus svg and fzp files depending on what was in the sketch to start with.

Ok I changed file name with .zip and when I went to unzip, I get this error message…”Unable to expand “Filename.zip” into “Desktop”. (Error 1 - Operation not permitted.)”…I did the same with a file that works and it unzipped fine…So can I still salvage my work or is it a lost cause?

Likely it is lost. At least without someone with special skills to recover data from a corrupt zip file. There are some technical ways that the code could (mostly) avoid that kind of problem, by writing the new file before erasing the old, then renaming after verification that the new version was successfully saved. You could look in the folder where the file was, to see if there is a similar named file with odd ending (or beginning). If it exists, it might be the previous version of the file. Just rename (copy) to change to end in .fzz. I do not know the internals of Frtizing well enough to know what process it goes through to save a file.

This is a Fritzing bug (they forgot to add the return code to the print statement, thus the %d instead of a number.) That said it usually means that the .fzz file is either corrupted or zero length (there have been reports of apparently properly saved, but zero length in the file system fzz files on linux before but it isn’t reproducable.) It is likely the crash occurred while writing the .fzz file and thus the data is lost (a disk being full is one possible cause of this!). For a project that you are working on for a long time it is a good bet to save a working copy of the .fzz file outside of Fritzing so you can go back to an earlier version if such a failure happens (they are usually rare though.)


I got that message as well when I wanted to take old files.
After looking at various posts on this topic I tried one solution to open the .fzz files with a zip program. I used 7-zip and inside the .fzz here was a .fz file. I extracted this .fz file and opened it with Fritzing, and… found it there without problem!!
I did that with the 3 files that had problems and all opened ok.
However, when I saved them as .fzz files, I was still unable to open them again.
Not sure what’s the problem, maybe something in Fritzing itself, but at least I can get my files back.
I am currently on .9.6.4 release
Hope that helps