Fix “App is Damaged Can’t Be Opened” Error Messages in Mac OS X

Nov 12, 2015 - 34 Comments

Mac App Store icon

Some Mac users have discovered they are unable to open some applications downloaded from the Mac App Store. When attempting to open an impacted app in Mac OS, a message stating “ is damaged and can’t be opened. Delete and download it again from the App Store.” Another variation is a pop-up window appearing asking a user to “Sign in to use this application on this computer” requesting an Apple ID and password.

The reason these app can’t be opened error messages are appearing may be because of a code signing security certificate expired, in which case this is not user error or anything to do with user involvement, it’s basically something with DRM that was messed up on the Mac App Store side but is now impacting some applications that were downloaded from there. Sometimes it can also be the result of a fluke issue when downloading an app from the App Store. Yes, this is a strange and frustrating error message, but it’s easily resolvable.

Resolving the “App is damaged and can’t be opened” Error in Mac OS X

This error message tends to appear in new versions of Mac OS X:

  1. Reboot the Mac, this alone may be sufficient to fix the problematic apps and remove the error message
  2. If a reboot does not fix the app, delete the application (just drag it to the Trash and empty), then re-launch the Mac App Store and download the app again via the Purchases tab or by searching for the app manually
  3. Open the once impacted apps again, they should now work fine

App damaged error message fix

Method 2: Fixing “App is damaged and can’t be opened” Error on Mac App Launch

If the above approach does not work, you may need to include a few additional steps:

  1. Delete the app in question from the Mac
  2. Log out of the Mac App Store
  3. Restart the Mac
  4. Upon reboot, open the Mac App Store and log in to the App Store again
  5. Re-Download the app in question

This “App is damaged and can’t be opened” error message occasionally happens even in modern macOS releases like macOS Big Sur. Fortunately, deleting the app, rebooting, and re-downloading it again usually resolves the issue quickly.


Resolving the “Sign in to use this application on this computer” Error in Mac OS X

Another variation of this error message may appear in older versions of Mac OS X:

  1. Close the “sign in to use this application” error dialog box when you see it, and reboot the Mac instead
  2. Upon reboot, open the Mac App Store and log in to your Apple ID to re-authenticate the Mac and all related apps
  3. Open the apps as usual

Sign in to use this application error message

That should be all that is required to get your apps working again in OS X.

The Quick App Error Fix for Advanced Mac Users: Killing a Process

You can target the storeaccountd processes via Activity Monitor if you want, or use the command line if you are comfortable with the Terminal:

sudo killall -v storeaccountd

There are typically two “storeaccountd” processes running, one as user, and one as root, and thus using killall on both is sufficient to resolve the issue.

Those interested in learning a bit more about the technical details behind these error messages can refer to this Twitter thread, which reveals the certificate that expired and speculates on various contributing factors.

Obviously if you haven’t seen these error messages on your Mac, you have nothing to worry about, and can go about your merry way. But, should you see them, at least know it’s a simple fix, the apps aren’t actually damaged, it was just an error on the Apple side of things with a quick remedy.

Note that you may sometimes see a similar but different error message stating the particular Mac “app is damaged and can’t be opened, you should move it to the Trash” which has a different potential set of solutions.


Related articles:

Posted by: Paul Horowitz in Mac OS, Troubleshooting


» Comments RSS Feed

  1. Naresh says:

    I revoked my developer id application certificate after that my app is not opening it’s crashing on launch and saying app can’t be opened. if i check crash report it’s saying code signature failed. Please help me with solution.

  2. sad says:

    Didn’t work been having this problem for days, anyone have an idea how to help? It isn’t even an App Store app and gene’s suggestion failed me.

  3. Gene says:

    See if this helps. I had a non-AppStore app that would not run because of the same error. I used the following to allow it to run again.

    1. Open a Terminal with appropriate privileges (“sudo bash” to make you root on most systems)

    2. Enter the following, substituting “AppName” with the real name of the app:

    xattr -cr /Applications/

    3. Press Enter to run the command.

    This should remove the flag currently set on the app.

    Here is a related tip for macOS Sierra. The option to allow apps from anywhere has been removed. Well, hidden actually. You can still open an unsigned app by Control-clicking the app and then choosing Open from the menu. It creates an exception for that app without the need to change how Gatekeeper functions.

    • ian says:

      solved thanks Gene

    • wouter says:

      This. The message is just BS, there is nothing wrong with the app, the problem is with MacOS. Re-install is a waste of time and maybe a bad idea, causing troubles like changed behaviour and GUI, compatibility issues with existing files , new bugs, etc.

  4. Jimbou says:

    Here the same with a macOS Sierra and the dropbox.dmg application for instance. Neither rebooting, App Store account signing out and in nor killing the storeaccountd processes worked. The error remains. Any further ideas or suggestions?

  5. pat says:


    this is how you solve Windows problem, not how you should solve mac problem. The fact that osx is having you reboot shows how bad things got over time. I have been a mac user for 20 years and I no longer tell friends and family to buy mac. This app is damaged issue is so annoying. It happens to me even after some app automatically updates….

    • Toby says:

      pat, despite the similarity to Windows, this is indeed how you solve the Mac problem here. Yes the Mac software quality has degraded, as has iPhone, letting Apple know they should fix it would be wise!

  6. Sean says:

    I am so disappointed with Apple. Fixing things that were working
    quite well until they went and”fixed’ it. Now it won’t work and I
    can’t get it download again from the APP Store. Put it all back
    under iTunes and don’t screw with it again. In other words put the
    APP store in the trash and split the options back to where they came from.

    Just STUPID

  7. K.S. says:

    Is there a fix for this error for apps outside of the MAS?

  8. keerthan says:

    unable to open DRMS mails in mac x os machine

  9. Mike says:

    Thank you for the article. But in my case it will not work. My app is no more available via app store. If I remove it will not be able to install it via app store again. Give a lot of bugs for it. — Now I remember the reasons against central app delivery.

  10. Wild Horse Fantasy says:

    What really gets me is they have the gall to have no way to contact them but phone. And email demands an order number and an OS (which in my case isn’t listed. It’s not like the OS is responsible for their screw up).
    Apple is about to lose a long time customer. I PAID for these apps. I do not have the OS for an update. I do not have high speed internet, it will take DAYS to redownload. They have NO RIGHT to screw this up and expect the CUSTOMER who already purchased the item to fix it.

  11. Jonathan says:

    Rebooting my Mac as suggested in this article did not make these error messages stop.

    What *has* worked for me (which another comment mentioned, but is not mentioned in the original article) is to sign out of the App Store (Store > Sign Out), then sign back in (see “Sign In” link under Quick Links)

  12. Tice says:

    This is why I hate the App Store and that kind of DRM. It happened while I was on vacation and without internet. “Great work” from Apple.

  13. Hank4162 says:

    Right in the middle of a major product release and marketing campaign that previously announced the release date, my small business lost the use of our web design and productivity tools used to update our product web site, causing us to miss our delivery date and lose customers. I’m so upset I could spit red hot nails.

    I appreciate this article as I’m back in business again but, unfortunately, it came too late to meet our release date.

    Thanks Apple… for your damage done.

    • diorama says:

      I can relate. Unfortunately, the feeling is that Apple doesn’t care much about the Mac, let alone OS X, and the Mac App Store is a long forgotten afterthought, which is why this happened. Can you imagine this happening to iOS apps? Hundred million people would be impacted. It wouldn’t happen. I fear that over the next few years, Apple will continue to push the iPhone and forget about the Mac, maybe entirely abandon it with poorly thought out touch-based “Pro” devices like iPad Pro. I guess then, we move to Linux or to Windows to be productive. Oh brother.

      • Hank4162 says:

        We already tried to introduce iPads into our workforce with disastrous results due to an update to the webkit after the fact. Our iPads crashed every time we accessed our corporate customer information system (what they were purchased for). Apple’s solution… spend hundreds of thousands of dollars having the vendor rewrite our CIS system to work around the bug.

        Apple didn’t fix the problem until a year later. By then we sent all of the iPads home to our employee’s children and wrote them off as a loss.

        Bringing any new Apple product into our corporate environment is an experiment that will not be repeated until Apple gets their act together. With this latest debacle, the signs aren’t good and faith has been further eroded.

  14. Ferrers says:

    I’ve signed into the App Store, updated some applications and they work…

    The problem is, some of my applications have been replaced by newer versions that require a newer version of OS X, that I can’t install on my hardware. Has anyone found a way round this?

    • Pete B says:

      I have the same problem, i.e. some older apps have been replaced by updated versions which are not compatible with my Mac OSX 10.6. I have sought help from Apple, but they just don’t answer specific questions, and they refuse to admit that Apple disabled the apps on my Mac! They even had the cheek to suggest that I seek old versions of apps from the developers! They don’t understand that I don’t want to instal a copy of an app with the same expired certificate. Apple won’t refund the purchase price of the apps they disabled. Apple expects me to update my OS, but I can’t do that without losing the use of other old software which needs Rosetta to run, and I don’t want to risk all the other problems which may come with a new OS!
      I have got the disabled apps to run as follows:
      System Preferences: System: Date&Time: untick Set…automatically: change date to before Nov2015: click Save. The ‘damaged’ apps now run, but only while the System Date is manually set to a date preceding the MAS Certificate Expiry.
      After using the apps, I reset the Date&Time to automatic (takes a little while to occur).
      I hope someone can suggest a permanent solution to this problem.

    • Pete B says:

      Good news! Apple released (27 Jan 2015) an update for OS X Snow Leopard which installs renewed intermediate signing certificates so we can run our old apps that need receipt validation. The old ‘damaged’ apps can now be run (require sign-in with AppStore password)! The new certificates extend their use into 2013. You can read the new certificate in an apps’ Package Contents: Contents /_MASReceipt/receipt. Apple’s update is available from

  15. dons1138 says:

    if i deleted the app, i will lose all my saved data!!!!

    awful awful mac

    • Dan says:

      Actually, no.

      You don’t lose any data if you simply drag an app-icon into the trash. (preferences- and cache-files remain if you don’t erase them separately)

      Just don’t use Launchpad or any kind of uninstaller (like AppZapper, AppDelete, CleanMyMac, etc.) to uninstall/delete the app!

      I deleted some apps this way and after reinstalling those apps via the MAS all settings were intact.

      Further, I could solve the above described problem by simply signing out and back in to the MAS. Apps can be launched again and are running fine.

      So try logging of/back in the MAS before deleting any apps, as this might already fix the problem.

      • Mark says:

        Thanks, signing out and then back in again solved the problem for me, too.

        This was just a minor annoyance for me, but I can definitely see why people wouldn’t be too happy about this.

  16. Alan says:

    I have the same issue with a game. Was running fine, then got the prompt “sign in to use this app”, now it will not run at all. Tried re-booting, deleting and re-installing the app, killing the storeaccountd process.

    The App will still not run.

    Very frustrating.

  17. Mike says:

    Having done the reboots and reinstall procedures and still not able to use my particular financial app I’m at a loss.

  18. Miso says:

    I had two apps that could not be fixed.

    One of the apps was just updated by the developer to address this specific problem and now that app works.

  19. Mark says:

    I don’t understand why all these explanations are the “simply just do this” type. Why does anyone think the Mac App Store has anything but vaporware? So you delete the app (which WAS A WORKING APP) and then go to re-download it only to find out that it is no longer offered, or they revised it (most likely to be incompatible with what you currently have). Then what? Time Machine to the rescue? Not even. Still broken and by remote control! No, resetting the date did not outwit the certificate after restoring the app. So tired of my valuable hours spent on this kind of crap Apple!!!!

    • Paul says:

      The first step is to reboot the Mac, which usually resolves the issue.

      The second step, of deleting and re-downloading the app, is secondary, and typically not necessary.

      For apps you have downloaded from the App Store before but are not available in general search, you can typically find them in your Purchases tab.

  20. Ralphy says:

    Two out of 3 apps were fixed with the delete reload scenario. The third one (RC Mini Racers) will not launch after reloading and several reboot. Restores and Resets (with Clean My Mac).
    Who knows when it might work again.

  21. K Man says:

    What if I don’t have Internet (or working properly). I can’t download with it timing out (@ the office at the moment, thank you Comcast).

    Who’s going to pay for the bandwidth? I have snow-bird parents and Comcast (again) won’t play nice. So they use Mifi type LTE only for their Internet. It’s slow and expensive.

    Apple? Apple?

  22. Bobby says:

    I still have a problem with the iFinance3 app. I can’t open it : sometimes the “Verifying” appears and the app doesn’t open. Sometimes nothing happens.
    I’ve tried rebooting and redownloading the app from the app store to no avail…

  23. Typical Yuppie says:

    Apple is sloppy these days, they don’t seem to care about the Mac. But hey, here’s a humungous iPad!

Leave a Reply


Shop on and help support OSXDaily!

Subscribe to OSXDaily

Subscribe to RSS Subscribe to Twitter Feed Follow on Facebook Subscribe to eMail Updates

Tips & Tricks


iPhone / iPad



Shop on Amazon to help support this site