Does anyone else get the "Installer Quit unexpectedly" error? I just upgraded to Sierra 2 weeks ago and did not have it before.

The rogue "Installer" program is a consequence of installing adware. You do not need to download or install anything to fix it. Removing it requires a methodical approach because its name is always changing.

Navigate to the following folder, and post its contents in a screenshot.

~/Library/LaunchAgents

To open that folder, copy the entire line above and paste it in the Finder's Go menu > Go to Folder... field. It should look like this:

Take a screenshot showing all that folder's contents, and post it in a reply. To take a screenshot read the Appendix in the following User Tip: Writing an effective Apple Support Communities question.

There will be additional instructions to follow.

For a description of how this may have occurred, how to avoid it in the future, and for Apple's recommended actions read How to install adware.

Review your Gatekeeper settings: OS X : About Gatekeeper - Apple Support. Gatekeeper is designed to help prevent you from inadvertently installing garbage software.

Here's what it said:

EtreCheck version: 3.1.3 (337)

Report generated 2016-11-22 09:52:39

Download EtreCheck from https://etrecheck.com

Runtime 1:45

Performance: Excellent

Click the [Support] links for help with non-Apple products.

Click the [Details] links for more information about that line.

Problem: Other problem

Description:

Virus

Hardware Information:ⓘ

iMac (Retina 5K, 27-inch, Late 2015)

[Technical Specifications] - [User Guide] - [Warranty & Service]

iMac - model: iMac17,1

1 3.2 GHz Intel Core i5 (i5-6500) CPU: 4-core

8 GB RAM Upgradeable - [Instructions]

BANK 0/DIMM0

4 GB DDR3 1867 MHz ok

BANK 0/DIMM1

Empty

BANK 1/DIMM0

4 GB DDR3 1867 MHz ok

BANK 1/DIMM1

Empty

Bluetooth: Good - Handoff/Airdrop2 supported

Wireless: en1: 802.11 a/b/g/n/ac

Video Information:ⓘ

AMD Radeon R9 M380 - VRAM: 2048 MB

iMac 5120 x 2880

System Software:ⓘ

macOS Sierra 10.12.1 (16B2657) - Time since boot: less than an hour

Disk Information:ⓘ

APPLE HDD ST1000DM003 disk0 : (1 TB) (Rotational)

[Show SMART report]

EFI (disk0s1) <not mounted> : 210 MB

Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB

Macintosh HD (disk2) / [Startup]: 1.02 TB (336.41 GB free)

Core Storage: disk1s2 23.55 GB Online

Core Storage: disk0s2 999.35 GB Online

APPLE SSD AP0032H disk1 : (24 GB) (Solid State - TRIM: Yes)

EFI (disk1s1) <not mounted> : 315 MB

Boot OS X (disk1s3) <not mounted> : 134 MB

Macintosh HD (disk2) / [Startup]: 1.02 TB (336.41 GB free)

Core Storage: disk1s2 23.55 GB Online

Core Storage: disk0s2 999.35 GB Online

USB Information:ⓘ

Seagate Expansion Desk

Broadcom Corp. Bluetooth USB Host Controller

Apple Inc. FaceTime HD Camera (Built-in)

Thunderbolt Information:ⓘ

Apple Inc. thunderbolt_bus

Gatekeeper:ⓘ

Mac App Store and identified developers

Unknown Files:ⓘ

~/Library/LaunchAgents/com.mediateem.refactor.update.plist

~/Library/Application Support/mediateem/mediateem.app/Contents/MacOS/Installer -evnt agnt -oprID 80801207|00291|1000019|0|0|1|0|000000000|14112016|04070903|OTA=|U2FmZUZpbmRlcg= =|R0I=|VW5pdGVkIEtpbmdkb20=|R29vZ2xl -dBrowser Safari

One unknown file found. [Check files]

System Launch Agents:ⓘ

[not loaded] 6 Apple tasks

[loaded] 171 Apple tasks

[running] 102 Apple tasks

System Launch Daemons:ⓘ

[not loaded] 41 Apple tasks

[loaded] 165 Apple tasks

[running] 104 Apple tasks

Launch Daemons:ⓘ

[loaded] com.adobe.fpsaud.plist (2016-10-26) [Support]

User Launch Agents:ⓘ

[loaded] com.google.keystone.agent.plist (2016-11-19) [Support]

[failed] com.mediateem.refactor.update.plist (2016-11-22) [Support]

User Login Items:ⓘ

iTunesHelper Application (2016-11-19)

(/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)

Google Drive Application (2016-11-12)

(/Applications/Google Drive.app)

Slack Application (2016-11-19)

(/Applications/Slack.app)

Messages Application (2016-11-19)

(/Applications/Messages.app)

Mail Application (2016-11-19)

(/Applications/Mail.app)

iTunes Application (2016-11-19)

(/Applications/iTunes.app)

Notes Application (2016-11-19)

(/Applications/Notes.app)

Dictation Application (2016-10-21)

(/System/Library/Input Methods/DictationIM.app)

Internet Plug-ins:ⓘ

FlashPlayer-10.6: 23.0.0.207 - SDK 10.9 (2016-11-19) [Support]

QuickTime Plugin: 7.7.3 (2016-10-21)

Flash Player: 23.0.0.207 - SDK 10.9 (2016-11-19) [Support]

3rd Party Preference Panes:ⓘ

Flash Player (2016-10-26) [Support]

Time Machine:ⓘ

Auto backup: YES

Volumes being backed up:

Macintosh HD: Disk size: 1.02 TB Disk used: 685.58 GB

Destinations:

Darren's Time Machine [Local]

Total size: 1.50 TB

Total number of backups: 7

Oldest backup: 21/11/2016, 11:19

Last backup: 21/11/2016, 17:21

Size of backup disk: Too small

Backup size 1.50 TB < (Disk used 685.58 GB X 3)

Top Processes by CPU:ⓘ

6% com.apple.SpeechRecognitionCore.speechrecognitiond

5% coreaudiod

4% WindowServer

3% DictationIM

2% fontd

Top Processes by Memory:ⓘ

1.30 GB com.apple.WebKit.WebContent(7)

1018 MB kernel_task

328 MB iTunes

311 MB Slack Helper(3)

303 MB com.apple.SpeechRecognitionCore.speechrecognitiond

Virtual Memory Information:ⓘ

1.78 GB Available RAM

16 MB Free RAM

6.22 GB Used RAM

1.76 GB Cached files

18 MB Swap Used

Diagnostics Information:ⓘ

Nov 22, 2016, 09:24:06 AM ~/Library/Logs/DiagnosticReports/Installer_2016-11-22-092406_[redacted].crash

com.fuzeday.Installer - /Users/[redacted]/Library/Application Support/mediateem/mediateem.app/Contents/MacOS/Installer

Nov 22, 2016, 08:51:50 AM Self test - passed

Nov 21, 2016, 08:53:10 AM ~/Library/Logs/DiagnosticReports/Installer_2016-11-21-085310_[redacted].crash

Nov 20, 2016, 07:59:35 PM ~/Library/Logs/DiagnosticReports/Safari_2016-11-20-195935_[redacted].crash

com.apple.Safari - /Applications/Safari.app/Contents/MacOS/Safari

Nov 20, 2016, 08:58:26 AM ~/Library/Logs/DiagnosticReports/Installer_2016-11-20-085826_[redacted].crash

Nov 19, 2016, 08:32:22 PM ~/Library/Logs/DiagnosticReports/Installer_2016-11-19-203222_[redacted].crash

Nov 19, 2016, 12:28:05 PM ~/Library/Logs/DiagnosticReports/TwitterToday_2016-11-19-122805_[redacted].cras h

com.twitter.twitter-mac.TwitterToday - /Applications/Twitter.app/Contents/PlugIns/TwitterToday.appex/Contents/MacOS/Tw itterToday

Nov 19, 2016, 11:14:09 AM /Library/Logs/DiagnosticReports/Google Drive_2016-11-19-111409_[redacted].cpu_resource.diag [Details]

/Applications/Google Drive.app/Contents/MacOS/Google Drive

Nov 19, 2016, 10:33:39 AM /Library/Logs/DiagnosticReports/com.apple.preferences.internetaccounts.remotese rvice_2016-11-19-103339_[redacted].cpu_resource.diag [Details]

/System/Library/PreferencePanes/InternetAccounts.prefPane/Contents/XPCServices/ com.apple.preferences.internetaccounts.remoteservice.xpc/Contents/MacOS/com.appl e.preferences.internetaccounts.remoteservice

That installer is from a peice of malware, likely from installing Adobe Flash Player. May be from MegaBackup or Advanced MacCleaner (both bad stuff). There are bound to be other pieces of that malware in your system. It has nothing to do with Sierra and you should trash it. Also, please download and run EtreCheck, created by one of own helpers here in ASC. It is a diagnostic tool that's very useful to us in finding problems. It will also give us further specs on your Mac. After it runs post the log file here. It will contain no personal information.

Here are your problem files:

Unknown Files: ⓘ

~/Library/LaunchAgents/com.mediateem.refactor.update.plist

~/Library/Application Support/mediateem/mediateem.app/Contents/MacOS/Installer -evnt agnt -oprID

Diagnostics Information: ⓘ

Nov 22, 2016, 09:24:06 AM ~/Library/Logs/DiagnosticReports/Installer_2016-11-22-092406_[redacted].crash

com.fuzeday.Installer - /Users/[redacted]/Library/Application Support/mediateem/mediateem.app/Contents/MacOS/Installer

Do you know how to make your invisible ~/Library visible? You'll need to do that to delete the problems. Also look in /Applications for MegaBackup or Advanced MacCleaner or both.

Only download Flash Player from either the official Adobe site or through System Preferences > Adobe Flash Player. Even then I have my doubts that some malware may have gotten attached to the download package. This issue is coming up fairly consistently.

System Preferences > Security & Privacy > General > Allow Apps Downloaded from:

Yes, delete the third one. Which is the first, fuzeday? Drag it to the trash.

Great! Thanks for the update.

You may wish to read Beware bogus Adobe Flash "installers". The only way to prevent installing adware is its recognition and avoidance.

Viruses, Malware and OS X

There are no viruses that can attack Mac.OS X. So, anti-virus programs are selling a cure for a disease that doesn't exist. And they are renowned for borking Mac systems.

A Mac can pick up malware but not if you just use common sense. You really have to actively invite some malware in for it to happen. That means downloading and knowingly giving your password for it to download. Mac provides all the protection you need with SIP (System Integrity Protection) About System Integrity Protection on your Mac - Apple Support

Ars Technica

http://arstechnica.com/apple/2015/09/os-x-10-11-el-capitan-the-ars-technica-revi ew/8/

Don’t be fooled by products that claim to clean, virus check or optimize your Mac. The only cleaning you need to do on a Mac is with a soft cloth.

If you do happen to download malware you can use MalwareBytes to get rid of it. Malwarebytes was developed by one of our own colleagues here in ASC. It gets rave reviews and is about the most proven anti-malware software for Mac.

Keep your security set to “App Store and identified developers” Don’t download software from third party sites.If you use torrents, don't. Torrents are a good way to pick up malware because it can hitchhike in on a download package and you’ll never know it.

Safari pop-ups are different and easier to deal with. In Safari 9.1 and later just close the window. For earlier versions force quit and hold the shift key while restarting Safari.

https://support.apple.com/en-us/HT203987

Finally, stay away from programs that purport to "clean your Mac". They can do damage to your system. Your Mac needs no cleaning in the first place. All the cleaning that is necessary is taken care of routinely by OS X.

I don't use torrents. I know exactly what it is, I sometimes watch football streams and the auto download flash players to the desktop, I usually delete them, but I've just set up this Mac and thought I actually need flash so I'll download it 😟

Do not download Sophos. All AV software and so-called cleaners are poison on a Mac. EtreCheck will give you the file path to the problem software. The installer should be in ~/Library/Application Support.

Yes, in Finder use your "Go" menu and enter the file path shown by EtreCheck report.

com.fuzeday.Installer - /Users/[redacted]/Library/Application Support

~/Library/LaunchAgents/com.mediateem.refactor.update.plist

~/Library/Application Support/mediateem/mediateem.app/Contents/MacOS/Installer -evnt agnt -oprID

Sorry for the edits, it's late and I got confused.

Thanks so much for this, and sorry for being a bit thick.

But to confirm, in GO I click 'Go To Folder' and put it in there and delete those three things?

I've deleted the 2nd one, the 3rd one looks like this, delete this?

I can't get the first one to work.

I have this problem, too. The Popup comes up several times a day. I don't know what installer they are talking about. I followed your advice above and downloaded EtreCheck. I ran the program twice and it now says my computer is clean.

Everything seems to be working as it should except I can't get into my Credit Union online banking site. All I get is a page full of computer language that I don't understand. It's not the **'s computer system as I can still access it from my iPod. All my other bookmarked links work, so I don't know what is the problem. Could it have something to do with the EtreCheck program?

I also had a problem with Safari when trying to access my ** account. I inadvertently typed in .com instead of .org to access my bank account and I got flashing popups and a voice that sounded like Darth Vader saying my virus has a virus and not to close the window or my hard drive would be deleted. They wanted me to call a number, which I didn't trust at all. It was very scary. I did force quit, anyway. I had just read your answer here that Macs are protected from viruses. Any thoughts?

Thank you so much.

I have this problem too, very very annoying. Is there anything we can delete or do we need virus software?