Unbelieveably Slow MacPro running El Capitan 10.11.6

I'm experiencing serious issues with my MacPro, and a lot of my problems seem to have surfaced when I moved over to El Capitan. My computer boots fine but takes an inordinate length of time - 10-15 minutes - to launch Apple Mail and Creative Suite's InDesign 2015 CC. It's frustrating and I am unsure of what to do. I'm a complete klutz when it comes to the "mechanics" of Macs and their operating system even though I've been working with them since my first SE and PageMaker 1.0. My Macs over the years have run sweetly and I've not encountered anything as what confronts me now. I'm not sure what to do - do I ditch the machine and buy another, or is my MacPro "salvageable"? I came across mention of EtreCheck on a post last evening so I downloaded and ran it today. I'm hoping someone can give me some pointers as to what I do next. Here's the EtreCheck report:

EtreCheck version: 2.9.13 (267)

Report generated 2016-08-11 18:03:53

Download EtreCheck from https://etrecheck.com

Runtime 19:37

Performance: Poor

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

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

Check Apple signatures: Enabled

Problem: Computer is too slow

Description:

Apple Mail and InDesign take long time to launch

Hardware Information: ⓘ

Mac Pro (Mid 2010)

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

Mac Pro - model: MacPro5,1

2 2.4 GHz Quad-Core Intel Xeon CPU: 8-core

8 GB RAM Upgradeable - [Instructions]

DIMM 1

1 GB DDR3 ECC 1066 MHz ok

DIMM 2

1 GB DDR3 ECC 1066 MHz ok

DIMM 3

1 GB DDR3 ECC 1066 MHz ok

DIMM 4

1 GB DDR3 ECC 1066 MHz ok

DIMM 5

1 GB DDR3 ECC 1066 MHz ok

DIMM 6

1 GB DDR3 ECC 1066 MHz ok

DIMM 7

1 GB DDR3 ECC 1066 MHz ok

DIMM 8

1 GB DDR3 ECC 1066 MHz ok

Bluetooth: Old - Handoff/Airdrop2 not supported

Wireless: en2: 802.11 a/b/g/n

Video Information: ⓘ

ATI Radeon HD 5770 - VRAM: 1024 MB

LED Cinema Display 1920 x 1200

System Software: ⓘ

OS X El Capitan 10.11.6 (15G31) - Time since boot: about 2 days

Disk Information: ⓘ

HL-DT-ST DVD-RW GH61N ()

WDC WD1001FALS-41Y6A0 disk1 : (1 TB) (Rotational)

EFI (disk1s1) <not mounted> : 210 MB

Macintosh HD (disk1s2) / : 999.35 GB (261.84 GB free)

Recovery HD (disk1s3) <not mounted> [Recovery]: 650 MB

WDC WD1500HLFS-01G6U3 disk0 : (150.04 GB) (Rotational)

EFI (disk0s1) <not mounted> : 210 MB

WORK IN PRO (disk0s2) /Volumes/WORK IN PRO : 149.70 GB (124.84 GB free)

USB Information: ⓘ

Imation ImationFlashDriv 7.74 GB

POCKET (disk3s1) /Volumes/POCKET : 7.74 GB (3.10 GB free)

Seagate Backup+ Desk 4 TB

disk5s1 (disk5s1) <not mounted> : 134 MB

Seagate Backup Plus Drive 02 (disk5s2) /Volumes/Seagate Backup Plus Drive 02 : 4.00 TB (2.86 TB free)

Brother HL-2140 series

Seagate Backup+ Desk M 4 TB

EFI (disk4s1) <not mounted> : 315 MB

Seagate Backup Plus Drive (disk4s2) /Volumes/Seagate Backup Plus Drive : 3.50 TB (126.14 GB free)

Apple Inc. Apple LED Cinema Display

Apple Inc. Display iSight

Apple Inc. Apple USB audio device

Apple, Inc. Keyboard Hub

Mitsumi Electric Apple Optical USB Mouse

Apple, Inc Apple Keyboard

Western Digital My Book 1234

Apple Inc. BRCM2046 Hub

Apple Inc. Bluetooth USB Host Controller

Gatekeeper: ⓘ

Mac App Store and identified developers

Kernel Extensions: ⓘ

/Applications/DiskWarrior.app

[not loaded] com.alsoft.Preview (5.0 - SDK 10.5 - 2014-12-03) [Support]

/Applications/Toast 10 Titanium/Toast Titanium.app

[not loaded] com.roxio.BluRaySupport (1.1.6 - 2012-09-27) [Support]

[not loaded] com.roxio.TDIXController (1.7 - 2012-09-27) [Support]

/System/Library/Extensions

[not loaded] com.seagate.driver.PowSecDriverCore (5.2.6 (26977) - SDK 10.4 - 2016-08-02) [Support]

[not loaded] com.wacom.kext.wacomtablet (Wacom Tablet 6.1.6-4 - 2016-08-02) [Support]

[not loaded] com.wdc.driver.1394.64.10.9 (1.0.1 - SDK 10.9 - 2016-08-02) [Support]

[loaded] com.wdc.driver.USB.64.10.9 (1.0.1 - SDK 10.9 - 2016-08-02) [Support]

/System/Library/Extensions/Seagate Storage Driver.kext/Contents/PlugIns

[not loaded] com.seagate.driver.PowSecLeafDriver_10_4 (5.2.6 (26977) - SDK 10.4 - 2015-01-31) [Support]

[not loaded] com.seagate.driver.PowSecLeafDriver_10_5 (5.2.6 (26977) - SDK 10.5 - 2015-01-31) [Support]

[not loaded] com.seagate.driver.SeagateDriveIcons (5.2.6 (26977) - SDK 10.4 - 2015-01-31) [Support]

Startup Items: ⓘ

RetroClient: Path: /Library/StartupItems/RetroClient

Startup items are obsolete in OS X Yosemite

System Launch Agents: ⓘ

[not loaded] 8 Apple tasks

[loaded] 149 Apple tasks

[running] 66 Apple tasks

[killed] 15 Apple tasks

15 processes killed due to insufficient RAM

System Launch Daemons: ⓘ

[failed] com.apple.csrutil.report.plist

[running] com.seagate.TBDecorator.plist (2013-10-12) [Support]

[not loaded] 45 Apple tasks

[loaded] 150 Apple tasks

[running] 83 Apple tasks

[killed] 11 Apple tasks

11 processes killed due to insufficient RAM

Launch Agents: ⓘ

[not loaded] com.adobe.AAM.Updater-1.0.plist (2016-08-09) [Support]

[failed] com.adobe.ARMDCHelper.cc24aef4a1b90ed56a...plist (2016-07-15) [Support]

[running] com.adobe.AdobeCreativeCloud.plist (2016-04-12) [Support]

[failed] com.adobe.CS4ServiceManager.plist (2010-09-16) [Support]

[failed] com.adobe.CS5ServiceManager.plist (2010-11-15) [Support]

[loaded] com.oracle.java.Java-Updater.plist (2014-07-31) [Support]

[running] com.teamviewer.teamviewer.plist (2012-10-01) [Support]

[running] com.teamviewer.teamviewer_desktop.plist (2012-10-01) [Support]

[running] com.wacom.wacomtablet.plist (2010-11-16) [Support]

Launch Daemons: ⓘ

[running] com.adobe.ARMDC.Communicator.plist (2016-07-15) [Support]

[running] com.adobe.ARMDC.SMJobBlessHelper.plist (2016-07-15) [Support]

[not loaded] com.adobe.SwitchBoard.plist (2013-01-11) [Support]

[running] com.adobe.adobeupdatedaemon.plist (2016-06-12) [Support]

[loaded] com.adobe.agsservice.plist (2016-04-12) [Support]

[loaded] com.adobe.fpsaud.plist (2016-06-29) [Support]

[loaded] com.adobe.versioncueCS4.plist (2010-09-16) [Support]

[not loaded] com.attotech.attomgtd.plist (2009-05-05) [Support]

[loaded] com.bombich.ccc.plist (2012-11-27) [Support]

[not loaded] com.bombich.ccc.scheduledtask.96191F55-0BA5-4914-A91E-40E96DD3703C.plist (2013-01-23) [Support]

[loaded] com.macpaw.CleanMyMac3.Agent.plist (2015-09-29) [Support]

[loaded] com.microsoft.office.licensing.helper.plist (2010-08-25) [Support]

[loaded] com.oracle.java.Helper-Tool.plist (2014-07-31) [Support]

[loaded] com.retrospect.engine.updater.plist (2012-04-19) [Support]

[not loaded] com.retrospect.retroengine.plist (2015-06-29) [Support]

[running] com.retrospect.retroisa.plist (2012-10-17) [Support]

[loaded] com.roxio.UpdateRetrospect.plist (2010-07-23) [Support]

[running] com.teamviewer.teamviewer_service.plist (2012-10-01) [Support]

User Launch Agents: ⓘ

[loaded] com.adobe.AAM.Updater-1.0.plist (2012-09-28) [Support]

[failed] com.adobe.ARM.[...].plist (2012-09-28) [Support]

[failed] com.adobe.ARM.[...].plist (2013-12-21) [Support]

[failed] com.adobe.ARM.[...].plist (2012-09-28) [Support]

[loaded] com.citrixonline.GoToMeeting.G2MUpdate.plist (2015-04-19) [Support]

[loaded] com.google.keystone.agent.plist (2016-07-12) [Support]

[loaded] com.macpaw.CleanMyMac3.Scheduler.plist (2016-07-05) [Support]

User Login Items: ⓘ

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

Wondershare Helper Compact Application (~/Library/Application Support/Helper/Wondershare Helper Compact.app)

DiskWarriorDaemonStarter Application (/Applications/DiskWarrior.app/Contents/Helpers/DiskWarriorStarter.app)

AdobeResourceSynchronizer Application Hidden (/Applications/Adobe Acrobat DC/Adobe Acrobat.app/Contents/Helpers/AdobeResourceSynchronizer.app)

CleanMyMac 3 Menu Application (/Applications/CleanMyMac 3.app/Contents/MacOS/CleanMyMac 3 Menu.app)

Other Apps: ⓘ

[loaded] com.adobe.Acrobat.Pro.46112

[running] com.adobe.CCLibrary.118112

[running] com.adobe.CCXProcess.118432

[running] com.adobe.InDesign.56032

[running] com.adobe.Photoshop.57952

[running] com.adobe.acc.AdobeDesktopService.163552.1900AE43-AC19-4EF9-A530-10707857FAF2

[running] com.adobe.accmac.118752

[running] com.etresoft.EtreCheck.292832

[loaded] com.fiplab.MemoryCleanHelper

[running] com.fiplab.memoryclean.89312

[running] com.google.Chrome.72672

[failed] com.jdibackup.JustCloud.autostart

[failed] com.jdibackup.JustCloud.backupstart

[failed] com.jdibackup.JustCloud.notify

[running] com.macpaw.CleanMyMac3.Menu.142752

[running] com.wacom.TabletDriver.161632

[running] com.wondershare.helper_compact.159712

[running] jp.co.canon.cijscannerregister.193952

[running] org.mozilla.firefox.69152

[loaded] 437 Apple tasks

[running] 222 Apple tasks

[killed] 26 Apple tasks

Internet Plug-ins: ⓘ

WacomNetscape: 1.1.1-1 (2010-11-16) [Support]

Default Browser: 601 - SDK 10.11 (2016-07-28)

AdobeExManDetect: AdobeExManDetect 1.1.0.0 - SDK 10.7 (2015-11-17) [Support]

Flip4Mac WMV Plugin: 2.3.8.1 (2011-01-14) [Support]

OfficeLiveBrowserPlugin: 12.3.4 (2012-09-28) [Support]

AdobeAAMDetect: 3.0.0.0 - SDK 10.9 (2016-06-12) [Support]

AdobePDFViewerNPAPI: 15.017.20053 - SDK 10.11 (2016-08-09) [Support]

FlashPlayer-10.6: 22.0.0.209 - SDK 10.9 (2016-07-17) [Support]

Silverlight: 5.1.41212.0 - SDK 10.6 (2016-05-17) [Support]

QuickTime Plugin: 7.7.3 (2016-07-28)

Flash Player: 22.0.0.209 - SDK 10.9 (2016-07-17) [Support]

iPhotoPhotocast: 7.0 - SDK 10.7 (2012-09-28)

SharePointBrowserPlugin: 14.6.6 - SDK 10.6 (2016-07-18) [Support]

AdobePDFViewer: 15.017.20053 - SDK 10.11 (2016-08-09) [Support]

WacomSafari: 1.1.1-1 (2010-11-16) [Support]

EPPEX Plugin: 3.0.5.0 (2009-07-30) [Support]

JavaAppletPlugin: Java 8 Update 91 build 14 (2016-05-06) Check version

User internet Plug-ins: ⓘ

CitrixOnlineWebDeploymentPlugin: 1.0.105 (2013-04-26) [Support]

3rd Party Preference Panes: ⓘ

Adobe Version Cue CS4 (2010-09-16) [Support]

Flash Player (2016-06-29) [Support]

Flip4Mac WMV (2011-01-14) [Support]

Java (2016-05-06) [Support]

Paragon NTFS for Mac ® OS X (2016-07-15) [Support]

Perian (2011-07-24) [Support]

Retrospect (2012-10-17) [Support]

Seagate Dashboard for Mac OSX (2015-06-09) [Support]

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: 737.51 GB

Destinations:

Seagate Backup Plus Drive [Local]

Total size: 3.50 TB

Total number of backups: 62

Oldest backup: 16/03/16, 12:56 PM

Last backup: 11/08/16, 4:31 PM

Size of backup disk: Excellent

Backup size 3.50 TB > (Disk size 999.35 GB X 3)

Top Processes by CPU: ⓘ

48% RetroISA

9% WindowServer

6% CEPHtmlEngine Helper(10)

4% kernel_task

2% plugin-container

Top Processes by Memory: ⓘ

1.18 GB RetroISA

1020 MB kernel_task

999 MB firefox

647 MB mdworker(21)

426 MB com.apple.WebKit.WebContent(5)

Virtual Memory Information: ⓘ

219 MB Free RAM

7.77 GB Used RAM (1.62 GB Cached)

10.51 GB Swap Used

Diagnostics Information: ⓘ

Aug 11, 2016, 02:44:49 PM ~/Library/Logs/DiagnosticReports/Mail_2016-08-11-144449_[redacted].crash

/Applications/Mail.app/Contents/MacOS/Mail

Aug 11, 2016, 12:29:16 PM ~/Library/Logs/DiagnosticReports/Mail_2016-08-11-122916_[redacted].crash

Aug 10, 2016, 09:28:05 PM ~/Library/Logs/DiagnosticReports/plugin-container_2016-08-10-212805_[redacted]. crash

/Applications/Firefox.app/Contents/MacOS/plugin-container.app/Contents/MacOS/pl ugin-container

Aug 10, 2016, 06:17:09 PM /Library/Logs/DiagnosticReports/RetroISA_2016-08-10-181709_[redacted].crash

/Library/Application Support/Retrospect/RetrospectInstantScan.bundle/Contents/MacOS/RetroISA

Aug 9, 2016, 09:54:17 PM Self test - passed

Aug 9, 2016, 09:06:51 PM ~/Library/Logs/DiagnosticReports/plugin-container_2016-08-09-210651_[redacted]. crash

Aug 9, 2016, 04:06:30 AM /Library/Logs/DiagnosticReports/RetroISA_2016-08-09-040630_[redacted].crash

Any advice will be gratefully accepted.

Cheers

TFC 1951 =|:O)