Thanks for the help. In response to your suggestion of doing EtreCheck, a copy of the report follows:
EtreCheck version: 3.4.6 (460)
Report generated 2017-10-12 12:47:38
Download EtreCheck from https://etrecheck.com
Runtime: 3:07
Performance: Good
Click the [Lookup] links for more information from Apple Support Communities.
Click the [Details] links for more information about that line.
Click the [Remove/Report] links to remove adware or update the whitelist of legitimate software.
Click the [Clean up] link to delete unused files.
Problem: Other problem
Description:
Suspected malware.
Hardware Information:ⓘ
iMac (27-inch, Mid 2011)
[Technical Specifications] - [User Guide] - [Warranty & Service]
iMac - model: iMac12,2
1 3.4 GHz Intel Core i7 (i7-2600) CPU: 4-core
16 GB RAM Upgradeable - [Instructions]
BANK 0/DIMM0
4 GB DDR3 1333 MHz ok
BANK 1/DIMM0
4 GB DDR3 1333 MHz ok
BANK 0/DIMM1
4 GB DDR3 1333 MHz ok
BANK 1/DIMM1
4 GB DDR3 1333 MHz ok
Handoff/Airdrop2: not supported
Wireless: en1: 802.11 a/b/g/n
iCloud Quota: 110.65 GB available
Video Information:ⓘ
AMD Radeon HD 6970M - VRAM: 1 GB
iMac 2560 x 1440
Disk Information:ⓘ
ST31000528AS disk0: (1 TB) (Rotational)
[Show SMART report]
EFI (disk0s1 - MS-DOS FAT32) <not mounted> [EFI]: 210 MB
Macintosh HD (disk0s2 - Journaled HFS+) / [Startup]: 999.35 GB (473.40 GB free)
Recovery HD (disk0s3 - HFS+) <not mounted> [Recovery]: 650 MB
HL-DT-STDVDRW GA32N ()
USB Information:ⓘ
USB20Bus
Apple Inc. FaceTime HD Camera (Built-in)
hub_device
General USB Flash Disk
USB Flash Disk disk2: (1.01 GB)
USB DISK (disk2s1 - MS-DOS FAT32) /Volumes/USB DISK : 1.01 GB (390 MB free)
USB2.0 Hub
HP Photosmart C5200 series
EPSON EPSON Scanner
Apple Inc. BRCM2046 Hub
Apple Inc. Bluetooth USB Host Controller
USB20Bus
hub_device
Seagate FreeAgent GoFlex
FreeAgent GoFlex disk1: (1 TB)
EFI (disk1s1 - MS-DOS FAT32) <not mounted> [EFI]: 210 MB
FreeAgent GoFlex Drive (disk1s2 - Case-sensitive Journaled HFS+) /Volumes/FreeAgent GoFlex Drive : 999.86 GB (126.27 GB free)
Apple Computer, Inc. IR Receiver
Apple Internal Memory Card Reader
Thunderbolt Information:ⓘ
Apple Inc. thunderbolt_bus
System Software:ⓘ
macOS High Sierra 10.13 (17A405) - Time since boot: about 2 hours
Configuration files:ⓘ
/etc/hosts - Corrupt!
Gatekeeper:ⓘ
Mac App Store and identified developers
Possible adware:ⓘ
Adware: /Library/LaunchDaemons/com.iobit.AMCDaemon.plist
One possible adware file found. [Remove/Report]
Clean up:ⓘ
com.adobe.ARM.[...].plist
/Applications/Adobe Reader.app/Contents/MacOS/Updater/Adobe Reader Updater Helper.app/Contents/MacOS/Adobe Reader Updater Helper semi-auto
Executable not found!
One orphan file found. [Clean up]
Kernel Extensions:ⓘ
/System/Library/Extensions
[loaded] com.f-secure.kext.fsauth (0.5.0) [Lookup]
[not loaded] com.sony.driver.dsccamFirmwareUpdaterType00 (1.1.0.10240 - SDK 10.6) [Lookup]
System Launch Agents:ⓘ
[not loaded] 9 Apple tasks
[loaded] 166 Apple tasks
[running] 113 Apple tasks
System Launch Daemons:ⓘ
[not loaded] 35 Apple tasks
[loaded] 183 Apple tasks
[running] 112 Apple tasks
Launch Agents:ⓘ
[not loaded] com.adobe.AAM.Updater-1.0.plist (Adobe Systems, Inc. - installed 2013-10-29) [Lookup]
[failed] com.adobe.ARMDCHelper.cc24aef4a1b90ed56a725c38014c95072f92651fb65e1bf9c8e43c37a2 3d420d.plist (Adobe Systems, Inc. - installed 2017-01-13) [Lookup]
[loaded] com.f-secure.relauncher.plist (Shell Script bd439549 - installed 2015-03-02) [Lookup]
[loaded] com.f-secure.trasher.plist (? db9f591e afc98041 - installed 2015-03-02) [Lookup]
[loaded] com.google.keystone.agent.plist (Google, Inc. - installed 2017-07-10) [Lookup]
[loaded] com.oracle.java.Java-Updater.plist (? dcf773c2 72ac4dde - installed 2017-08-31) [Lookup]
[running] com.robohippo.HippoConnectAgent.plist (RoboHippo LLC - installed 2015-06-10) [Lookup]
[running] com.sony.SonyAutoLauncher.agent.plist (? a756a1bd 2d86074a - installed 2013-11-02) [Lookup]
Launch Daemons:ⓘ
[loaded] com.adobe.ARMDC.Communicator.plist (Adobe Systems, Inc. - installed 2017-01-13) [Lookup]
[loaded] com.adobe.ARMDC.SMJobBlessHelper.plist (Adobe Systems, Inc. - installed 2017-01-13) [Lookup]
[loaded] com.adobe.SwitchBoard.plist (? 68cad67 0 - installed 2012-12-28) [Lookup]
[loaded] com.adobe.fpsaud.plist (? 2afb3af7 ebe01993 - installed 2017-09-25) [Lookup]
[not loaded] com.apple.installer.cleanupinstaller.plist (? 1963bf56 0 - installed 2017-10-08)
[loaded] com.f-secure.fsavd.dbhelper.plist (? 4eb45576 56ffdb01 - installed 2015-03-02) [Lookup]
[running] com.f-secure.fsavd.plist (? e79c8422 722d540 - installed 2015-03-02) [Lookup]
[loaded] com.f-secure.fsmac.firewall.plist (? 1bf81563 1e7f70cf - installed 2015-03-02) [Lookup]
[loaded] com.f-secure.fsmac.fsupdated_guts2.plist (Shell Script 783d8cd7 - installed 2015-03-02) [Lookup]
[loaded] com.f-secure.fsmac.licensetool.plist (? 38629c09 4c50fa5e - installed 2015-03-02) [Lookup]
[running] com.f-secure.orspclient.plist (Shell Script 4d2e8df8 - installed 2015-03-02) [Lookup]
[loaded] com.google.keystone.daemon.plist (Google, Inc. - installed 2017-07-26) [Lookup]
[running] com.iobit.AMCDaemon.plist (? ce7f599b 71907915 - installed 2014-09-08) Adware! [Remove/Report]
/Library/Application Support/AMC/AMCDaemon
[loaded] com.microsoft.autoupdate.helper.plist (Microsoft Corporation - installed 2017-04-18) [Lookup]
[loaded] com.microsoft.office.licensing.helper.plist (? 6d8cb30e 8b29c3ef - installed 2012-04-02) [Lookup]
[loaded] com.oracle.java.Helper-Tool.plist (Shell Script e3fefdd2 - installed 2017-07-21) [Lookup]
[not loaded] com.robohippo.HippoConnectDaemon.plist (RoboHippo LLC - installed 2015-06-10) [Lookup]
User Launch Agents:ⓘ
[loaded] com.adobe.AAM.Updater-1.0.plist (Adobe Systems, Inc. - installed 2013-10-29) [Lookup]
[failed] com.adobe.ARM.[...].plist (? 560d19c8 0 - installed 2013-01-15) [Lookup] - /Applications/Adobe Reader.app/Contents/MacOS/Updater/Adobe Reader Updater Helper.app/Contents/MacOS/Adobe Reader Updater Helper: Executable not found!
[running] com.akamai.single-user-client.plist (? 120f4368 f4f704a9 - installed 2017-09-26) [Lookup]
[loaded] com.dropbox.DropboxMacUpdate.agent.plist (Dropbox, Inc. - installed 2017-09-11) [Lookup]
[loaded] com.skype.skype.shareagent.plist (Skype Communications S.a.r.l - installed 2017-09-29) [Lookup]
User Login Items:ⓘ
iTunesHelper Application (Apple, Inc. - installed 2017-09-13)
(/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
Dropbox Application
(/Applications/Dropbox.app)
Internet Plug-ins:ⓘ
AdobeExManDetect: AdobeExManDetect 1.0.0.0 (installed 2012-12-28) [Lookup]
FlashPlayer-10.6: 27.0.0.159 (installed 2017-10-10) [Lookup]
QuickTime Plugin: 7.7.3 (installed 2017-10-02)
AdobePDFViewerNPAPI: 17.012.20098 (installed 2017-08-30) [Lookup]
AdobePDFViewer: 17.012.20098 (installed 2017-08-30) [Lookup]
Flash Player: 27.0.0.159 (installed 2017-10-10) [Lookup]
o1dbrowserplugin: 5.41.3.0 (installed 2015-12-15) [Lookup]
SharePointBrowserPlugin: 14.7.3 (installed 2017-04-18) [Lookup]
googletalkbrowserplugin: 5.41.3.0 (installed 2015-12-11) [Lookup]
Silverlight: 5.1.10411.0 (installed 2013-03-22) [Lookup]
JavaAppletPlugin: Java 8 Update 144 build 01 (installed 2017-08-31) Check version
User internet Plug-ins:ⓘ
WebEx64: 1.0 (installed 2013-07-11) [Lookup]
ZoomUsPlugIn: 3.0.46193.0828 (installed 2014-08-28) [Lookup]
Safari Extensions:ⓘ
None
3rd Party Preference Panes:ⓘ
Akamai NetSession Preferences (installed 2017-09-11) [Lookup]
Safe Anywhere Mac Settings (installed 2015-04-03) [Lookup]
Flash Player (installed 2017-09-25) [Lookup]
Java (installed 2017-08-31) [Lookup]
Time Machine:ⓘ
Skip System Files: NO
Mobile backups: OFF
Auto backup: YES
Volumes being backed up:
Macintosh HD: Disk size: 999.35 GB Disk used: 525.94 GB
Destinations:
FreeAgent GoFlex Drive [Local]
Total size: 999.86 GB
Total number of backups: 187
Oldest backup: 9/17/14, 12:49 AM
Last backup: 10/12/17, 11:22 AM
Size of backup disk: Too small
Backup size 999.86 GB < (Disk used 525.94 GB X 3)
Top Processes by CPU:ⓘ
3% WindowServer
1% kernel_task
0% fontd
0% mds
0% mdworker
Top Processes by Memory:ⓘ
1.06 GB kernel_task
464 MB com.apple.WebKit.WebContent
425 MB com.apple.WebKit.WebContent
321 MB mds_stores
238 MB Safari
Top Processes by Network Use:ⓘ
Input Output Process name
1 MB 537 KB Mail
350 KB 107 KB mDNSResponder
310 KB 82 KB com.apple.WebKit.Networking
143 KB 177 KB Dropbox
221 KB 16 KB CalendarAgent
Top Processes by Energy Use:ⓘ
5.82 WindowServer
0.74 fsavd
0.62 netsession_mac
0.26 Dropbox
Virtual Memory Information:ⓘ
9.53 GB Available RAM
3.83 GB Free RAM
6.47 GB Used RAM
5.71 GB Cached files
0 B Swap Used
Software installs (last 30 days):ⓘ
iFax: 3.11 (installed 2017-09-17)
iFax: 3.12 (installed 2017-10-06)
Adobe Flash Player: (installed 2017-10-10)
Install information may not be complete.
Diagnostics Events (last 3 days for minor events):ⓘ
2017-10-10 07:26:01 mdworker Crash [Open]
Cause: import fstype:hfs fsflag:480D000 flags:40000005E diag:0 isXCode:0 uti:com.apple.mail.emlx plugin:/Library/Spotlight/Mail.mdimporter - find suspect file using: sudo mdutil -t 30448965