Someone just sent me a file over WeTransfer. After downloading it turns out to be a .zip-file, but when I double-click on it to unzip as usual, the Archive Utility does start the unzipping but ends in an error each time, claiming the .zip-file is broken.
I’m pretty sure the .zip-file isn’t broken… what can I do ?
Even though OSX/macOS’s built-in Archive Utility is your default choice for zipping and unzipping files and folders, it turn out not to be the best choice for unzipping. (Especially .zip-files created on Windows PCs seem to be problematic every now and then…)
The solution is simple : just use an other app to unzip.
Since the latest version of OSX (entitled “macOS Sierra) has been yesterday, I wanted to install it on my Mac. I clicked on “download” in the Mac AppStore and the download started ; on the dedicated product page I could see the status bar filling up and finally stating “downloaded”… but then, nothing happened…
The download wouldn’t install…
I re-checked if macOS Sierra does support my Mac, it does. So I tried restarting the AppStore-app, I tried logging out my iCloud/AppStore-account & than logging back in, I tried rebooting my Mac, I tried rebooting in SafeMode, I tried FirstAid in the Disk Utility app, I tried clicking 10 times on the “downloaded” button repeatedly, I tried installing the DeBug-menus & cleaning the AppStore cache, I tried deleting the hidden AppStore downloads folder… and I tried various command line solutions found online in the Terminal app… nothing helped… I am still stuck with the button under the macOS Sierra icon saying “downloaded”… and nothing happens…
What can I do ?
You are probably not (really) going to like this answer, because this will set you back hours & hours, in which you can’t use your Mac ; but it’s the only way known to solve this, and you need to have a recent TimeMachine backup (or alike) for it :
shut down your Mac
disconnect all cables from your Mac (except your keyboard & mouse if you haven’t got a MacBook)
restart your Mac, and be quick to press the [CMD]+[R] key-combo during startup (your Mac will now start up in Recovery Mode)
in the “OS X Utilities” window that appears, select Restore From TimeMachine Backup and click Continue
in the next “Restore Your System” window, click Continue
now first make sure that your Mac can connect to your TimeMachine-harddisk by plugging in it’s USB-cable, plugging in your Ethernet-network-cable or connect to your WiFi router
then select the hard drive that has your TimeMachine backups on it and click Continue
in the next window, make sure you select the most recent backup that is from before you tried to download macOS Sierra ; only if you’re sure you’ve selected the right backup, proceed and click Continue
now wait (or do something more useful in the mean time) and wait and wait ; this is going to take hours and hours ; putting back a TimeMachine backup this way will go a a speed of about 30BG per hour, so if your hard drive is 500GB it may take you about 15 hours (yes, an entire night and an entire morning…)
finally, once the TimeMachine backup-reinstall is done, your Mac will restart… just let it
then, when logged in, open the Mac AppStore-app and notice that the button under the macOS Sierra now says “download” ; click on it
after the download has completed, you should now see the installer window popup on your screen… proceed from there…