My iMac suddenly strated running very slow and taking forever to boot up

Before you do anything backup your computer. Then run Apple's Hardware Test in extended mode at least 2-3 times back to back. While AHT is not the most reliable test, however if it finds errors they are correct. The reason for running it 2-3 times back to back is because it does not always find errors the first time. The test can be lengthy, up to 3 hours each pass.

The reason I say to run AHT is my guess is your internal HD is failing, what you are describing is a classic description of a failing HD. Do not wait, begin the the backup immediately and then run AHT 2-3 times.

Good luck and post results.

If this started happening without your having made any changes and without a warning of low disk space, then it's likely that the startup drive, or some other hardware component, is failing. Back up all data immediately, then run Apple Diagnostics or the Apple Hardware Test.

Even if the test is negative, you should make a "Genius" appointment at an Apple Store to have the machine tested more thoroughly.

Welcome!

First, slow booting can be caused by a failing hard drive. From your recovery partition, launch Disk Utility and let it verify your drive.

You installation profile is rather clean but I see a couple of possible miscreants:

1) Two WD apps are starting every time you start the computer. Remove all WD software. It was bad with pre-Mavericks Mac OS versions and got worse in Mavericks. I've used it on both PowerPC and Intel Macs and it slowed them in very case. often taking the form of stalls where the computer would stop reacting for 10-30 seconds, then go back to normal. I still use WD drives, just not their bone-headed software. Let Time Machine do that job.

2) I assume you need some form of remote server access and that is why the Citrix software is there. If it has the "phone home frequently, that will slow booting and general operations, especially if you have a slow internet connection. As it is probably work-related, there's not much you can do about that one.

3) If you use DivX, make sure it is fully updated. Outdated versions have been a little flaky in the past

There is one log-in item with which I'm not familiar--Xmarks for Safari Support. What does it do?

If you are going to run so many startup items, you probably should add RAm although the Etrecheck report doesn't say you are stressing what you have. That could be simply the difference in running EtreCheck right after a startup and running it after the comptuer has been working for a day. You computer can hold up to 32 GB RAM--8GB (add two 2GB modules to the open slots you have) would be an economical upgrade easily accomplished at home---takes 5-10 minutes. My 13-year old grandson just added two modules to Gramma's iMac yesterday and he's never done it before!

Allan

iMac 2010 27-inch; quad-core 2.93Ghz i7; 12GB RAM; OS 10.6.8

Yeah my mac also starting slowing out of know where. I bought a external hard drive and it was taking forever to backup, I forgot to plug in the mac so overnight it powered down thus not completing the backup. I haven't done one yet now because I read you have to deleyed the undone backup first or it will cause more problems.

I did a test on that EtreCheck and below is the results, the only thing I saw that I think could be a problem is this:

User Launch Agent

failed com.apple.CSConfigDotMacCert-[...]@me.com-SharedServices.Agent.plist

Thanks all!

EtreCheck version: 1.9.12 (48)

Report generated July 5, 2014 at 12:29:20 PM PDT

Hardware Information:

MacBook Pro (13-inch, Mid 2012) (Verified)

MacBook Pro - model: MacBookPro9,2

1 2.9 GHz Intel Core i7 CPU: 2 cores

8 GB RAM

Video Information:

Intel HD Graphics 4000 - VRAM: (null)

Color LCD 1280 x 800

System Software:

OS X 10.9.4 (13E28) - Uptime: 0 days 2:48:20

Disk Information:

TOSHIBA MK7559GSXF disk0 : (750.16 GB)

EFI (disk0s1) <not mounted>: 209.7 MB

Macintosh HD (disk0s2) / [Startup]: 749.3 GB (624.35 GB free)

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

HL-DT-ST DVDRW GS31N

USB Information:

Apple Inc. Apple Internal Keyboard / Trackpad

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller

Apple Computer, Inc. IR Receiver

Apple Inc. FaceTime HD Camera (Built-in)

Thunderbolt Information:

Apple Inc. thunderbolt_bus

Gatekeeper:

Mac App Store and identified developers

Launch Daemons:

[loaded] com.adobe.fpsaud.plist Support

[loaded] com.google.keystone.daemon.plist Support

[loaded] com.microsoft.office.licensing.helper.plist Support

[running] com.prosoftnet.idrivedaemon.plist Support

[running] com.prosoftnet.idsyncdaemon.plist Support

[running] com.prosoftnet.idwebdaemon.plist Support

Launch Agents:

[loaded] com.google.keystone.agent.plist Support

User Launch Agents:

[failed] com.apple.CSConfigDotMacCert-[...]@me.com-SharedServices.Agent.plist

[loaded] com.citrixonline.GoToMeeting.G2MUpdate.plist Support

User Login Items:

iTunesHelper

Dropbox

TextExpander

IDriveMonitor

RoboFormIcon

Internet Plug-ins:

Flip4Mac WMV Plugin: Version: 3.2.0.16 - SDK 10.8 Support

FlashPlayer-10.6: Version: 14.0.0.125 - SDK 10.6 Support

QuickTime Plugin: Version: 7.7.3

Flash Player: Version: 14.0.0.125 - SDK 10.6 Support

Default Browser: Version: 537 - SDK 10.9

o1dbrowserplugin: Version: 5.4.2.18903 Support

SharePointBrowserPlugin: Version: 14.3.8 - SDK 10.6 Support

googletalkbrowserplugin: Version: 5.4.2.18903 Support

Silverlight: Version: 5.1.20513.0 - SDK 10.6 Support

Safari Extensions:

RoboForm: Version: 1.8.4

Audio Plug-ins:

BluetoothAudioPlugIn: Version: 1.0 - SDK 10.9

AirPlay: Version: 2.0 - SDK 10.9

AppleAVBAudio: Version: 203.2 - SDK 10.9

iSightAudio: Version: 7.7.3 - SDK 10.9

iTunes Plug-ins:

Quartz Composer Visualizer: Version: 1.4 - SDK 10.9

User Internet Plug-ins:

CitrixOnlineWebDeploymentPlugin: Version: 1.0.105 Support

Picasa: Version: 1.0 - SDK 10.4 Support

3rd Party Preference Panes:

Flash Player Support

Flip4Mac WMV Support

Time Machine:

Mobile backups: OFF

Auto backup: NO - Auto backup turned off

Volumes being backed up:

Macintosh HD: Disk size: 697.84 GB Disk used: 116.37 GB

Destinations:

Seagate Backup Plus Drive [Local] (Last used)

Total size: 2

Total number of backups: (null)

Size of backup disk: Adequate

Backup size 2 > (Disk used 116.37 GB X 3)

Time Machine details may not be accurate.

All volumes being backed up may not be listed.

Top Processes by CPU:

3% WindowServer

0% Folder Actions Dispatcher

0% IDriveDaemon

0% aosnotifyd

Top Processes by Memory:

336 MB firefox

172 MB Finder

131 MB softwareupdated

115 MB mds_stores

98 MB com.apple.WebKit.WebContent

Virtual Memory Information:

4.79 GB Free RAM

1.88 GB Active RAM

463 MB Inactive RAM

897 MB Wired RAM

366 MB Page-ins

0 B Page-outs

AY Stoked

Please create your own thread, some one will be happy to help. What you are doing his threadjacking someone else's thread. This can be confusing because the causes are likely different. In addition you have a MacBook Pro and this is an iMac thread.

Good luck!

Sorry about that! And thanks.

I've had exactly the same problem, did a clean install which didn't fix it.

This morning I've uninstalled Western Digital Drive Utilities (which removes the WDDriveUtilityHelper login item) and my system seems to be running ok now.