Easy to create, good compression, wide software support – Zip files are an excellent way to save disk space and network bandwidth.
Until, that is, one of your archives becomes corrupted, or a download is incomplete. You may then find your archiving tool refuses to work with the file at all, in which case you’ll need some third-party help if your data is to be recovered.
In theory this shouldn’t be a problem. A quick Google search for something like “fix zip file” brings up a host of promising tools, some of which are free, and all promising that they’re the ideal choice for all your archive repair needs.
But, as usual, life is rarely quite this simple. There are a huge number of ways in which Zip files can be damaged, and the results you’ll see from repair tools will vary greatly: some may recover all your data, others may miss a few files, and one or two might not find anything at all.
Who can you rely on, then? There was only one way to find out. We had to test 8 of the top-ranked programs for ourselves.
How we tested
We started by creating a test archive containing a collection of Microsoft Sysinternals utilities, 95 files in total, producing a Zip file a little more than 11MB in size. This was quite small, but the large number of files compensated for this, and would ensure that recovering everything could be a challenging task.
Next, we created a copy of the file and split it in two, saving the first half as “Incomplete.zip”. This would help us simulate perhaps the most common zip issue, where a Zip file has only been partly downloaded.
For our second test, we took the original archive and replaced the first two bytes of the header with zeroes. This alone is enough to prevent many programs from recognising a Zip archive at all, but hopefully our repair tools would be smarter than that.
For our third test, we created a copy of the archive where 256 bytes in the middle of the file had been zeroed, simulating some possibly significant corruption.
For our fourth and final test, we zeroed 256 bytes at the end of file, again just to see how that would affect results.
And that was it, our test suite was finished. It was time to bring on the contenders.
1. Advanced Zip Repair – £24
Advanced Zip Repair (AZR) is a compact, easy-to-use recovery tool. Just choose the file to be repaired, specify where you’d like to save the results if you like, click Start Repair, and that’s about it.
An Options tab does reveal more options, though, if you need them. Particularly interesting is the option to “Use AZR’s exe stub when repairing self-extracting files”, so if the executable part of a self-extracting EXE archive is damaged beyond repair then the program may still be able to get it working. And elsewhere, the options to repair spanned files, or fix a bunch of Zips in one operation, are also welcome.
How did it perform in our tests, though? AZR did well with our “Incomplete.zip”, correctly recovering all 51 regular files, and part of the 52nd – full marks.
The corrupt header test proved trickier, though – for some reason AZR only extracted 94 files from that test Zip (the first was missing).
The program was back on form with our third and fourth tests, however, featuring corruption in the middle and end of the file, recovering everything.
Overall, then, AZR is straightforward in operation, has a good feature set, and produced generally good recovery performance.
Score: 4/5
AZR: Packing plenty of functionality into its compact, easy-to-use interface
2. DiskInternals ZIP Repair – Free
This app keeps the archive recovery process simple through its use of a very basic wizard. Point the program at your corrupt file, view the results of whatever its found, and these are saved to disk in a click – very easy.
This extreme simplicity does mean you can forget about options like recovering multiple Zips in one go, for instance. And there are no configuration options to customise how the recovery process works. Still, by way of compensation the program scored well in our tests.
DiskInternals ZIP Repair recovered everything there was to find in Incomplete.zip (it didn’t warn us that one file was incomplete, but that’s something we’d find out soon enough).
Just as with AZR, the program recovered 94 out of 95 files in the corrupt header test. But it did better in the final two tests, retrieving everything there was to find despite corruption in the middle and end of our archives.
DiskInternals ZIP Repair is basic, then, and short on features. But decent recovery performance, and the fact that it’s free of charge, meant that the program scored excellently.
Score: 5/5
FREE OPTION: It’s small. And it’s basic. But ZIP Repair is free, and it works (mostly), and that’s good
3. Nucleus Kernel Zip – £17.70 ($29)
Nucleus Kernel Zip has a more complex interface than many of the competition here, with a toolbar, menus, buttons and more. But take a closer look and you’ll see it follows a familiar wizard-style approach; point the program at your broken archive, click Next, and it’ll search the file for recoverable data.
At least, that’s the plan. You may well run out of patience before this process is complete, though, as Nucleus Kernel Zip proved astonishingly slow, taking something like 5 minutes to scan each megabyte of data (the others needed only seconds).
If you do hang on, however, the recovery results are generally acceptable. Kernel Zip recovered all the data in our Incomplete.zip and final two recovery tests, for instance, while (as with many others) missing just a single file in the corrupt header test.
This isn’t good enough to justify the wait, however, especially for a commercial tool, when there are capable (and much faster) free programs available elsewhere. And so we were only able to award Nucleus Kernel Zip a disappointing score.
Score: 2/5
COMES UP SHORT: Short on options and extremely slow, there’s little to recommend Nucleus Kernel Zip
4. Object Fix Zip – Free
Object Fix Zip is a free Zip recovery tool with a simple, wizard-style interface, which is able to carry out several actions on your chosen files. It can simply check Zip files for corruption, extract everything it can from an archive, or try to create a new good archive from an existing broken Zip.
This all looked great. Until, that is, we put the program through our tests.
When the program was faced with “Incomplete.zip”, for instance, it complained that this was an “Incomplete ZIP file”. We know, that’s why we installed it in the first place, but Object Fix Zip refused to extract a single file.
It was the same story with our test archive which we’d corrupted at the end. This was enough to trigger another “Incomplete ZIP file” alert, and again the program recovered nothing at all.
Object Fix Zip wasn’t fooled by the corrupt header, though, correctly retrieving all our test files. And it did well with our test archive which was zeroed in the middle, recovering all but the file affected by that corruption.
As it’s free, there’s no harm in having Object Fix Zip around, just in case other recovery tools fail. It isn’t nearly reliable enough to be your main Zip repair tool, though, and for that reason we can only award it a poor score.
Score: 2/5
DISAPPOINTING: Object Fix Zip proved disappointing, failing entirely on two of our tests
5. Recover Data for Zip – £17.70 ($29)
Recover Data for Zip created something of a mixed first impression.
The clear interface, ability to process multiple files at once, and recover selected files from an archive, rather than all of them, proved welcome pluses.
But the fact that the program hadn’t been updated since 2008, its inability to display its own help file, and the spelling mistake on the opening screen all helped to detract from the overall effect.
Still, performance in our tests proved reasonable. Recover Data for Zip was able to locate all 52 files in our Incomplete.zip archive (although there was no warning that one of the files was itself incomplete). It recovered 94 out of 95 files from the archive with the corrupt header, and extracted everything from the archives with corruption at the middle or end of the file.
More than acceptable, then. But the fact that DiskInternals ZIP Repair does something similar free of charge, while Recover Data for Zip will cost you almost £18, means the program lags a little behind the top packages.
Score: 4/5
POOR FEATURES: While easy to use, Recover Data for Zip doesn’t have quite enough features or functionality to justify its asking price
6. Stellar Phoenix Zip Recovery 1.0 – £28.60 ($46.80)
Stellar Phoenix Zip Recovery features a bulky interface which is almost as overblown as the program’s name, with menus and large toolbar buttons attempting to persuade you that it’s packed with functions and features. Although the reality is that it’s quite basic, only able to open a single Zip file at a time, and with no configuration tweaks and very few extra features.
There’s nothing wrong with Stellar Phoenix Zip Recovery‘s core engine, though. In our tests, it recovered everything possible from our incomplete archive, and the files corrupted in the middle, and at the end. Better still, it actually recovered everything from the archive with the corrupt header, even the first file that many others managed to miss.
Whether this is enough to justify the premium price, around £28.60, is another matter. Still, if other archive recovery tools aren’t up to the task then this one may well be worth a look, and we scored it impressively.
Score: 5/5
BIG INTERFACE: Get past the bulky interface and you’ll find Stellar Phoenix Zip Recovery does a great job of restoring your broken archives
7. ZipRecover – £31.19
ZipRecover takes a simple, straightforward approach to archive fixing, with an attractive wizard-style interface which asks you exactly what you’d like to repair, and a report that delivers useful details on everything that was recoverable.
The results in our Incomplete.zip test were excellent, too. Not only did the program find all 52 recoverable files, but it also clearly highlighted the one that was broken, something very few of the competition managed to do. And it also allows you to select files individually for recovery, so if you’re only interested in one or two key documents, then you can extract only those and ignore the rest.
And the good news continued elsewhere, with ZipRecover detecting all the files in each of our test “corrupt” archives, including the full 95 in the file with the corrupt header (not 94, as many of the competition believed).
You’d expect nothing less for the most costly package in our lineup, of course. And it still doesn’t include as many features and configuration options as the powerful AZR. Still, its excellent repair abilities mean ZipRecover has to score the best.
Score: 5/5
CLEAN: ZipRecover’s clean interface is easy to use, and it effortlessly passed all our repair tests
8. ZipRepair Pro – £18.30 (£29.95)
ZipRepair Pro has perhaps the most complete feature set here, with options to repair individual or multiple archives, the ability to repair spanned Zips, full support for Zip64 and more. Windows XP-style task panes make using the program straightforward, too.
Its performance in our tests started well, with ZipRepair Pro accurately extracting 51 files from the incomplete archive, and highlighting the remaining broken file.
The program then went with the crowd in the corrupt header test, though, correctly identifying 94 of the 95 available files. Oddly, it reported finding only 93, though, and the same confusion occurred with the other “corrupt” file tests, as 95 file names were listed but it reported only 94.
Maybe this issue was caused by something specific to our test files. And as long as ZipRepair Pro actually recovers your data, what’s displayed in the interface is only secondary. It could lead to some confusion, though, and as a result ZipRepair Pro scored less than it could have done,
Score: 3/5
CONFUSING: ZipRepair Pro regularly reported recovering one less file than it actually had, for some obscure reason
Conclusion
So what’s the best choice for Zip repairs, then? That really depends on you.
If you don’t use Zip files that often, and they don’t hold critical files anyway, or you’re just short of cash, then DiskInternals Zip Repair will probably be just about good enough. It’s not exactly packed with features, but the program is very easy to use, and our tests revealed that it’s just as capable at archive recovery as many of the commercial competition.
If you need the best possible recovery performance, though, and you’re willing to pay for it, then our choice would be ZipRecover. It’s expensive at £31.19, but its ease of use, detailed reporting, and the way it passed every one of our tests perfectly suggest it could be worth the money.
Post by