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

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 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.

Facing the same issue. This is what I did :

• bought a new MBP 2017 with pre-installed 10.12.x
• clean installed 10.13.1 after erasing Macintosh HD
• As a last step of clean install, transferred data from old MBP (mid-2010) using migration assistant

Now, when I click on a transferred file, first time it opens as expected. If I close it and try to re-open it by clicking on it again, it shows a message saying this file is damaged and move it to trash.

What is the solution? I can't use my new MBP without the data!

I utilized the migration assistant and still am getting the errors on files that are downloaded, even .zip files being opened by the default Mac app.

I am not sure if it is related, but I also cannot change the General Security settings to accept Apps downloaded from App Store and identified developers. I can change the radio button but it will revert back to App Store only when I pull up the screen again.

I have the same problem. I can't even open a PDF. System preferences keeps reverting to App Store only, even though I changed it to App Store and identified developers. MacOS 10.13.1. Yes, previewing the file works perfectly. A fix is urgently needed.

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!

I have same issues; I also used Migration Assistant to move files; it corrupted the permissions on my .ssh/ directory and on the encryption keys inside there. It complains that PDFs that are openable on my wife's older MacBook or on my Late 2012 MBP running the latest version of software.

This is the most annoying bug I've encountered in the 30 years I've been a Mac User...

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.

"file damaged can't be opened move to trash" Same here. On a mid 2010 15" MacBook Pro os 10.13.1.

Now if I return to my studio I can open it from my late 2012 mac mini os 10.13.1 from the iCloud desktop. When I re save it will become openable again from the MacBook Pro. Really killing my work flow. BTW the files are SketchUp Pro 2018. Seems to be related to iCloud. Ideas?

I had the same issue but had kept all my old files on my previous Mac - so simply copied them over again and they seem to be working ok now. However, I cannot download software and install - my system preferences keeps reverting to "apple only" even though I keep unchecking it. Trying the gatekeeper disable to see if that helps. Am on 10.13.2, only had this new MBP 5 days and hating this OS already - nothing but problems (wi-fi keeps dropping too, yet another fix)

Everything is getting worse suddenly.

Some two days old pdf became unreadable. And also pngs or keynote file.

It seems to be random. Foto library seems to be ok at the moment, but who knows...

What's happening Apple?

Every helps appreciated!

I'm on 10.13.2 after migrating from my previous iMac. The same problem. Can't even change the security option "Allow apps downloaded from" to "App store and identified developers"

It got "unchecked" after each reboot :-(

I'm so dissapointed with Apple - their software is getting worse with each release. I have spent HUGE amount of money on a new iMac 2017 because the old one (2009) was suppose to have problems with High Sierra.

Migration was a nightmare for the first time and now this problem.

APPLE what the ... has happened to you !

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.

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.