Late 2015 iMac running very slowly

Everything on my iMac is slow.

I've run Etrecheck (report below) but do not know what to do with the results.

Grateful for any help.

Thanks

EtreCheck version: 4.1 (4A162)

Report generated: 2018-03-02 09:20:00

Download EtreCheck from https://etrecheck.com

Runtime: 10:28

Performance: Poor

Problem: Computer is too slow

Major Issues:

Anything that appears on this list needs immediate attention.

Poor performance - EtreCheck report took over 10 minutes to run. This is very unusual.

Minor Issues:

These issues do not need immediate attention but they may indicate future problems.

Heavy RAM usage - This machine is using a large amount of RAM.

Clean up - There are orphan files that could be removed.

Unsigned files - There is unsigned software installed. It appears to be legitimate but should be reviewed.

System modifications - There are a large number of system modifications running in the background.

Hardware Information:

iMac (21.5-inch, Late 2015)

iMac Model: iMac16,2

1 2.8 GHz Intel Core i5 (i5-5575R) CPU: 4-core

8 RAM Not upgradeable

BANK 0/DIMM0

4 GB DDR3 1867 ok

BANK 1/DIMM0

4 GB DDR3 1867 ok

Video Information:

Intel Iris Pro Graphics 6200 - VRAM: 1536 MB

iMac 1920 x 1080

Drives:

disk0 - APPLE HDD HTS541010A9E662 1.00 TB (Mechanical)

Internal SATA 3 Gigabit Serial ATA

disk0s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk0s2 [Core Storage Container] 999.35 GB

disk1 - Macintosh HD (Journaled HFS+) 998.98 GB

disk0s3 - Recovery HD (Journaled HFS+) [Recovery] 650 MB

disk2 - ST4000LM024-2AN17V 4.00 TB (Mechanical)

External Thunderbolt 6 Gigabit Serial ATA

disk2s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk2s2 - I**x (Journaled HFS+) 4.00 TB

disk3 - Samsung M3 Portable Samsung M3 Portable 2.00 TB

External USB 5 Gbit/s

disk3s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk3s2 - L****g (Journaled HFS+) 2.00 TB

Mounted Volumes:

disk1 - Macintosh HD 998.98 GB (630.87 GB free)

Journaled HFS+

Mount point: /

disk2s2 - I**x 4.00 TB (1.27 TB free)

Journaled HFS+

Mount point: /Volumes/I**x

disk3s2 - L****g 2.00 TB (636.48 GB free)

Journaled HFS+

Mount point: /Volumes/L****g

Network:

Interface en0: Ethernet

Interface en5: iPhone

Interface en1: Wi-Fi

802.11 a/b/g/n/ac

One IPv4 address

4 IPv6 addresses

Interface en4: Bluetooth PAN

Interface bridge0: Thunderbolt Bridge

iCloud Quota: 1.97 GB available

System Software:

macOS High Sierra 10.13.3 (17D102)

Time since boot: About 2 days

System Load: 2.01 (1 min ago) 2.07 (5 min ago) 1.99 (15 min ago)

Security:

Unsigned Files:

Launchd: /Library/LaunchDaemons/com.microsoft.office.licensing.helper.plist

Executable: /Library/PrivilegedHelperTools/com.microsoft.office.licensing.helper

Details: Exact match found in the whitelist - probably OK

Launchd: /Library/LaunchAgents/com.oracle.java.Java-Updater.plist

Executable: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Resources/Java Updater.app/Contents/MacOS/Java Updater -bgcheck

Details: Exact match found in the whitelist - probably OK

Launchd: /Library/LaunchDaemons/com.CoreUpdates.agent.plist

Executable: /Applications/CoreUpdates/CoreUpdates -guid 61784816683841322 -source mm-1724

Launchd: /Library/LaunchDaemons/com.oracle.java.Helper-Tool.plist

Executable: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Resources/Helper-Tool

Details: Exact match found in the whitelist - probably OK

Launchd: /Library/LaunchDaemons/com.citrix.ctxusbd.plist

Executable: /Library/Application Support/Citrix Receiver/ctxusbd

Details: Exact match found in the whitelist - probably OK

Launchd: ~/Library/LaunchAgents/com.adobe.AAM.Updater-1.0.plist

Executable: /Library/Application Support/Adobe/OOBE/PDApp/UWA/UpdaterStartupUtility

Details: Exact match found in the whitelist - probably OK

Launchd: /Library/LaunchDaemons/com.adobe.SwitchBoard.plist

Executable: /Library/Application Support/Adobe/SwitchBoard/SwitchBoard.app/Contents/MacOS/launch.switchboard

Details: Exact match found in the whitelist - probably OK

Launchd: /Library/LaunchDaemons/com.OptiBuy.agent.plist

Executable: /Applications/OptiBuy/OptiBuy -guid 61784816683841322 -source mm-1724 -brand OptiBuy -dt 1497712481 -home ~ -tracking_url http:/events.optibuymac.com

Launchd: /Library/LaunchAgents/com.adobe.AAM.Updater-1.0.plist

Executable: /Library/Application Support/Adobe/OOBE/PDApp/UWA/UpdaterStartupUtility

Details: Exact match found in the whitelist - probably OK

Kernel Extensions:

/Library/Application Support/Citrix Receiver

[Not Loaded] CitrixGUSB.kext (Citrix Systems, Inc., 12.4.0 - SDK 10.9)

System Launch Agents:

System Launch Daemons:

Launch Agents:

Launch Daemons:

User Launch Agents:

User Login Items:

iTunesHelper Application (Apple, Inc. - installed 2018-01-29)

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

Dropbox Application

(/Applications/Dropbox.app)

Internet Plug-ins:

MeetingJoinPlugin: 1.0 (installed 2017-01-06)

Flip4Mac WMV Plugin: 3.0.0.126 (installed 2012-10-04)

Silverlight: 5.1.10411.0 (installed 2012-10-05)

FlashPlayer-10.6: 28.0.0.161 (installed 2018-02-06)

QuickTime Plugin: 7.7.3 (installed 2018-02-03)

Flash Player: 28.0.0.161 (installed 2018-02-06)

CitrixICAClientPlugIn: 12.4.0 (installed 2017-02-28)

SharePointBrowserPlugin: 14.7.2 (installed 2017-03-22)

AdobePDFViewer: 10.1.2 (installed 2012-02-06)

iPhotoPhotocast: 7.0 (installed 2010-03-31)

Scorch: Unknown (installed 2015-01-14)

JavaAppletPlugin: Java 8 Update 161 build 12 (installed 2018-01-22)

3rd Party Preference Panes:

Flash Player (installed 2018-02-01)

Flip4Mac WMV (installed 2012-09-15)

Java (installed 2018-01-22)

Paragon NTFS for Mac ® OS X (installed 2015-02-26)

Trusteer Endpoint Protection (installed 2017-11-30)

Time Machine:

Skip System Files:

Mobile backups: No

Auto backup: Yes

Volumes being backed up:

Macintosh HD: Disk size: 998.98 GB - Disk used: 368.11 GB

Destinations:

L***e [Local] (Last used)

Total size: 4.00 TB

Total number of backups: 56

Oldest backup: 2017-06-22 20:54:34

Last backup: 2018-03-01 20:19:17

Top Processes by CPU:

Top Processes by Memory:

Top Processes by Network Use:

Top Processes by Energy Use:

Virtual Memory Information:

Software Installs (past 30 days):

Clean up:

/Library/LaunchAgents/com.citrix.ReceiverHelper.plist

/usr/local/libexec/ReceiverHelper.app/Contents/MacOS/ReceiverHelper

Executable not found

/Library/LaunchAgents/com.citrix.ServiceRecords.plist

/usr/local/libexec/ServiceRecords.app/Contents/MacOS/ServiceRecords

Executable not found

/Library/LaunchAgents/com.citrix.AuthManager_Mac.plist

/usr/local/libexec/AuthManager_Mac.app/Contents/MacOS/AuthManager_Mac

Executable not found

Diagnostics Information (past 7 days):

2018-03-01 20:52:24 Microsoft Outlook.app Hang

2018-02-28 19:01:25 Mail.app Hang

End of report