After High Sierra Update all files report "damaged and can't be opened"

I found this link that fixed the issue properly.

https://macperformanceguide.com/blog/2017/20171124_1510-macOS-HighSierra-AppleCo reRot.html

The key command is below. Open Terminal and cd to the directory containing your "Damaged files"

xattr -d com.apple.quarantine *.pdf *.dmg

This fixed all my issues

I think I found the fix for this. http://osxdaily.com/2015/05/04/disable-gatekeeper-command-line-mac-osx/

I added back the checkbox allowing apps downloaded from Anywhere to run and that allows me to open PDFs, run installers for downloaded software, etc.

Note that I presume that this makes me more vulnerable to viruses, but I'm pretty careful about where I download stuff and what kinds of attachments I click on.

I had the same problem after using migration assistant to move my files over to a new iMac from a 2012 iMac. The behavior was unusual. for example, I could open an .jpg in Preview once, but if I tried to view it immediately afterward a second time I got the damaged file message. I tried resetting permissions using the terminal in utilities with no result. Finally after spending a few hours on the phone with Apple support they concluded that the operating system on my new iMac must be damaged. After reloading the operating system, the problem was solved. Apple support did a wonderful job of patiently working with me to solve the issue.

Check this discussion on StackExchange: sierra - Gatekeeper preventing from opening files from Finder (launching apps is fine) - Ask Different

I had the same issue, the above fixed it. The file /var/db/gkopaque.bundle was damaged (zero bytes) which was the root of the issue. Replacing this file with a known good copy completely eliminated the "damaged file" message.

This works WITHOUT disabling Gatekeeper, which from a security perspective is a much better solution for everyone.

I have reported this fix to Apple Support so hopefully word gets out there. It took me a long time to track this down, and I'm really thankful to the person on StackExchange who was persistent enough to keep digging until a solution was found.

I suggest deleting the User Account, and using Migration Assistant to restore that account from the Time Machine backup.

Migration Assistant can do that: Move your content to a new Mac - Apple Support.

I have the latest 10.13.2 and I have this issue too. Changing security setting to Preferences>Security&Privacy>Allow apps downloaded from>"Mac App Store and identified developers" is NOT WORKING! When you close the tab and reopen Preferences, you see the setting is back to the option "Mac App Store".

The only temporary solution available is to use terminal and disable the Gatekeeper:

sudo spctl --master-disable

Beware, when you try to change settings from "Anywhere" to "Mac App Store and identified developers", the bug is back and you cannot install anything again! Reopen the preferences, the option "anywhere" is away. You have to repeat the terminal command above.

Yea ... running 10.13.3, done migration from mbp 2013 to a mbp 2015 have same issue . Fixed by disabling gatekeeper, hope a later update fixes this because it's counter productive to do a migration and it corrupting/mistrusting your apple signed files ...

I ran into the same problem after using the Migration Assistant to move files from an iMac 2015 running Sierra to a new iMac 2017 running High Sierra (10.13.3). I couldn't open any file that was downloaded from the Internet including .pdfs nor files from email attachments, or even files I copied on to the machine post migration. While the previously referenced gatekeeper fix did work, it's not something I wanted to rely on because of the increased risk. I spent quite a bit of time with Apple Care changing permissions on the file system, etc.; it didn't work. Also the problem impacted all users on the system including a new user created after the migration. Finally, I reinstalled the OS and that seems to have fixed everything.

Even better to change e.g all files in Documents folder

xattr -rd com.apple.quarantine ~/Documents

/Rob

I carried out similar changes to others described here, i upgraded using Migration Assistant from MacBook Pro 2012 to a new MacBook Pro 2017 and experienced the same errors as others, first open of file was ok, 2nd one was not and presented the error. I tried the gatekeeper fix and that worked, but i didn't want to leave that switched off.

I contacted Apple Support who suggested that i needed to migrate to another user account to try and fix the issue but i would need to speak to a senior adviser who wasn't available. When i closed the chat i continued to set up my MacBook and ran cleanmymac3 which i have a license for as there was a lot of files etc i would imagine as part of migration. I found 8GB that could be deleted which i accepted and ran, on completion i've discovered that the issue i had with corrupted files is now resolved. I don't know what process it went through as it just does its thing and saves space, but whatever it has done its deleted or changed whatever was causing the problem. Im not sure if anyone else here has the software that can give this a try and see if they get the same result.

1. Backup old Mac fully to Time Machine disk

2. On the new Mac hold Cmd+R to boot from Recovery

3. Choose Restore from Time Machine backup and choose the disk from step 1

4. Let the system do its thing, it should then bootup and be useable.

This issue seems to occur due to Migration Assistant doing a shoddy job of converting HFS+ to APFS on the fly.

Can anyone else confirm this solution?

Thank you

This problem hit me last night. The gatekeeper fix did not work. Plus, System Preferences is one of the “damaged” apps so I can’t use it. So is Terminal, had to run that from a Recovery reboot.

The damaged apps problem is user level though, because I have an alternate account on this machine and apps that are damaged in my primary will launch on the alternate. Reinstalling MacOS does not nelp. I guess I will have to delete my primary account and rebuild it. Days lost for that.

This is looking like an easy High Sierra trap to fall into.

Fixed for me in 10.13.2

I have the same problem. After direct migration from 2014 MBP to 2016 MBP I have SOME PDF’s, PPT’s and XLSX’s that appear to be corrupted and don’t open directly from Finder. If I open them directly from Acrobat Reader or Office, they open and are editable without a problem.

I have tried moving, saving again, renaming. Nothing fixes the issue.

Apple, please fix this.

Having the same problem ... used Migration Assistant from late 2012 MacBook Pro Retina to new MacBook Pro 2017. Both on High Sierra 10.13.1. While it's possible to get around the individual situations by resetting the gatekeeper in terminal, this is a pain. A "holistic" fix would be welcome!