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Unzipping old files

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Unzipping old files

Postby paulbaggott » Sun Dec 03, 2017 12:04 pm

About eight or nine years ago on buying a new Mac Pro, I compressed everything on the old drive to a zipped file in an attempt to save everything.

Since then, on successive Mac Pros I've never been able to unzip this file using the Disc Utility. It goes through all the motions over a couple of hours only to say it can't do it.

Does anyone know if there is there another method or a piece of software that might be more successful in opening this zipped file?
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Re: Unzipping old files

Postby Kwackman » Sun Dec 03, 2017 12:14 pm

I thought (could be wrong) you simply double click on a zipped file to unzip it on a mac? I didn't think Disc Utility was involved in either zipping or unzipping?

Other than that, he only thing I remember from unzipping was to make sure there is enough space for it to uncompress to.

Hopefully someone more clued up on this will be a long shortly.
Desmond? Are you out there?

*EDIT* Found this page...
https://goo.gl/MBGUuT
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Re: Unzipping old files

Postby paulbaggott » Sun Dec 03, 2017 12:51 pm

Hello Kwackman.

Yeah, I double click it and it does it's business then says it can't complete after a couple of hours.
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Re: Unzipping old files

Postby resistorman » Sun Dec 03, 2017 3:06 pm

The archive may be damaged. Here’s an article on repairing one from Terminal... don’t try it on your only copy!

https://computers.tutsplus.com/tutorial ... -mac-49294
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Re: Unzipping old files

Postby paulbaggott » Thu Dec 07, 2017 7:54 pm

Hello Resistorman,

Many thanks for that link.

Terminal is very relevant to my needs and I'm sure it would have worked.

But...

The bit he missed out was what to type into Terminal to point it to the problematic zip.

The video said put the broken zip file into the Home folder. Unfortunately I don't have enough room on that particular drive for Terminal to extract and create another file (it's 104GB in size).

The Zip file in question is on an external drive where there is plenty of room. Unfortunately I don't know how to direct Terminal to the relevant folder on that drive.

Any ideas?
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Re: Unzipping old files

Postby desmond » Thu Dec 07, 2017 8:23 pm

Type the command up to before the filename, and drag the file into the terminal - terminal will insert it's full file path.

Or just start with by typing "/Volumes/" and hit tab and a few letters to autocomplete the drive name and keep going down the folder names until you get to the file.
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Re: Unzipping old files

Postby paulbaggott » Fri Dec 08, 2017 3:05 pm

Hello Desmond,

Tried it but this what happened (the zip file is called 'oldmac.zip' and I dragged it in after typing 'zip -F ');

I typed...

zip -F -b/Volumes/OLD\ PROJECTS/3\ .VERY\ OLD\ PROJECTS/oldmac.zip oldmac.zip

the response was...

zip warning: fix options -F and -FF require --out:
zip -F indamagedarchive --out outfixedarchive

I typed...

zip -F -b/Volumes/OLD\ PROJECTS/3\ .VERY\ OLD\ PROJECTS/oldmac.zip oldmac.zip --out pleasework.zip

the response was...

Fix archive (-F) - assume mostly intact archive
zip warning: No .zip file found
(If all you have are splits (.z01, .z02, ...) and no .zip, try -FF)
zip I/O error: No such file or directory
zip error: File not found or no read permission (oldmac.zip)

I typed...

zip -FF -b /Volumes/OLD\ PROJECTS/3\ .VERY\ OLD\ PROJECTS/oldmac.zip oldmac.zip --out pleasework.zip

the repose was...

Fix archive (-FF) - salvage what can
zip I/O error: Not a directory
zip error: Temporary file failure (/Volumes/OLD PROJECTS/3 .VERY OLD PROJECTS/oldmac.zip/zig8icUe


I'm guessing/hoping I haven't put the path in correctly? Is that right?

By the way, does Terminal recognise copied and pasted commands?
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Re: Unzipping old files

Postby desmond » Fri Dec 08, 2017 3:17 pm

Try:

zip -FF /Volumes/OLD\ PROJECTS/3\ .VERY\ OLD\ PROJECTS/oldmac.zip --out ./oldmac_fixed.zip

This will read your oldmac.zip file, and put it's fixed version into the current directory (where you started terminal from) as I believe you didn't have enough space on the external drive to store another copy...
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Re: Unzipping old files

Postby paulbaggott » Sat Dec 09, 2017 12:19 pm

Hello Desmond,

So close, yet so far.

I typed in what you said and hey presto, Terminal started to do its stuff!

Initially, there was a lot of Bandstand stuff being extracted which I'd forgotten I'd ever bought.

But...

It suddenly stopped with this message...

zip I/O error: Bad address
zip error: Output file write failure (write error on zip file)
Pauls-Mac-Pro:~ paulbaggott$

Is this the end of the road?

By the way, I typed in the following as instructed,..

zip -FF /Volumes/OLD\ PROJECTS/3\ .VERY\ OLD\ PROJECTS/oldmac.zip --out ./oldmac_fixed.zip

...just in case I've made an error there.

The 104GB file is on a disk that has 1.7TB of space. So there should be enough room I would have thought.
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Re: Unzipping old files

Postby desmond » Sat Dec 09, 2017 12:31 pm

I don't know, it wasn't my suggestion to try that utility, I have no experience with it.

A 100GB zip file is *huge* though it might just be that the software doesn't support anything of that size - it might cap out at 2 or 4GB like other 32 bit software, maybe.

The output file is being written to your home folder on your system drive in the command above as you mentioned previously there wasn't space on your drive for another copy of the file - if you *do* want to put it back on the disk the original file is on in the same place, you want to specify the full output path to the same place:

zip -FF /Volumes/OLD\ PROJECTS/3\ .VERY\ OLD\ PROJECTS/oldmac.zip --out /Volumes/OLD\ PROJECTS/3\ .VERY\ OLD\ PROJECTS/oldmac_fixed.zip

As you've found out, compressing a whole heap of stuff into one single massive zipfile is just not a good idea.

If this tool isn't working for you, your next task is to google "zip recovery" or "zip repair" and start to try various solutions in the hope something will work. A lot of these tools are on Windows, so it might help to try on a Windows machine.
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Re: Unzipping old files

Postby paulbaggott » Sun Dec 10, 2017 9:06 am

Hello Desmond,

I think you might be right. Terminal gets to a point then stops, waiting for another command. So I'm guessing it can only cope with so much, then it gets tired.

At least I know that the stuff in that file is accessible (probably), so thanks for the suggestions and help you and resistorman have given me.

Does anyone know if there are people who specialise in this sort of thing? Maybe online? I would be happy to pay someone to extract the files having come this far (as long as it's not too much).
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Re: Unzipping old files

Postby paulbaggott » Tue Dec 12, 2017 10:52 am

Just tried Remo Repair. It worked on the file for three days solid but posted a '...quit unexpectedly' message.
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Re: Unzipping old files

Postby Forum Admin » Tue Dec 12, 2017 11:46 am

Have you tried using the utility called The Unarchiver ?
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Re: Unzipping old files

Postby job » Tue Dec 12, 2017 12:34 pm

It might also be worth trying 7zip. You'll likely need Windows though as the Mac version isn't comparable. You can also look inside with 7zip and extract individually. Although i don't know if you can do that if the headers are damaged. I'd give it a shot :thumbup:
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Re: Unzipping old files

Postby Forum Admin » Tue Dec 12, 2017 12:39 pm

The Unarchiver is brilliant in my experience, and I've not found a file it would not decompress/unzip. However... I've never tried it on a single file archive that's 104Gb in size!!! :o :o
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Re: Unzipping old files

Postby jagraphics » Tue Dec 12, 2017 6:27 pm

Assuming you have a copy of the file I would unzip doing an "extract" that actually removes the file as it extracts it. Thus the resultant zip file should be a lot smaller than 104GB. The repacking might change the order of the files and let you unpack some more. It might also simply kill the file which is why you need to use a copy :-)

Then try extracting with some wild cards like *.VST *.doc or what ever. This might be able to bypass the corrupted file. Eventually you will end up with a very much smaller zip file with very few files in it.

Finally NEVER do a zip file that big again. Multiple smaller ones may not be quite as efficient but they are easier to stop, move and hopefully any problems will affect a smaller set of files.

Note1:The advice above is worth exactly wha you have paid for it. No liability is assumed.
Note2 : Make a back up of everything first.
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Re: Unzipping old files

Postby desmond » Tue Dec 12, 2017 6:33 pm

Just a thought - when you originally compressed the files into a zipfile, did you actually test the zipfile worked then?

Given that it's such a massive file, I'd be surprised the zip format handled it at all! What zip tool did you use to compress it? The Mac's inbuilt "Compress" tool in the finder?

Some other things to try that have worked for some in the same boat:

https://superuser.com/questions/114011/extract-large-zip-file-50-gb-on-mac-os-x
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