Mac running slow suddenly

Question

Dear All,
My mid-2012 13" MacBook Pro suddenly became extremely slow yesterday evening. I restarted it several times, installed the latest software updates without any improvement. This morming I did the following:
- I removed com.adobe.aaa.updater-1.0.plist from the /Library/LaunchAgents as I saw in the discussion that this could be a problem
- I ran EtreCheck (report below)
Surprisingly everything seems now back to normal (?). But I'm concerned something might be wrong. Particularly: should I be worried about the disk errors? Should I run a disk repair in DiskUtility?
Many thanks for your help,
Julien
Problem description:
mac book running extremely slow suddenly
EtreCheck version: 2.2 (132)
Report generated 4/20/15, 10:21 AM
Download EtreCheck from http://etresoft.com/etrecheck
Click the [Click for support] links for help with non-Apple products.
Click the [Click for details] links for more information about that line.
Hardware Information: ℹ️
    MacBook Pro Intel Core i5, Intel Core i7, 13" (Mid 2012)
    MacBook Pro - model: MacBookPro9,2
    1 2.9 GHz Intel Core i7 CPU: 2-core
    8 GB RAM Upgradeable
        BANK 0/DIMM0
            4 GB DDR3 1600 MHz ok
        BANK 1/DIMM0
            4 GB DDR3 1600 MHz ok
    Bluetooth: Good - Handoff/Airdrop2 supported
    Wireless:  en1: 802.11 a/b/g/n
    Battery: Health = Normal - Cycle count = 344 - SN = 9G309005SD3MB
Video Information: ℹ️
    Intel HD Graphics 4000
        Color LCD 1280 x 800
System Software: ℹ️
    OS X 10.10.3 (14D131) - Time since boot: 0:43:39
Disk Information: ℹ️
    APPLE HDD ST750LM022 disk0 : (750.16 GB)
        EFI (disk0s1) <not mounted> : 210 MB
        Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB
        Macintosh HD (disk1) / : 748.93 GB (305.69 GB free) - 2 errors
            Encrypted AES-XTS Unlocked
            Core Storage: disk0s2 749.30 GB Online
    HL-DT-ST DVDRW  GS31N 
USB Information: ℹ️
    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: ℹ️
    Apple Inc. thunderbolt_bus
Gatekeeper: ℹ️
    Mac App Store and identified developers
Kernel Extensions: ℹ️
        /Library/Application Support/VirtualBox
    [loaded]    org.virtualbox.kext.VBoxDrv (4.3.6) [Click for support]
    [loaded]    org.virtualbox.kext.VBoxNetAdp (4.3.6) [Click for support]
    [loaded]    org.virtualbox.kext.VBoxNetFlt (4.3.6) [Click for support]
    [loaded]    org.virtualbox.kext.VBoxUSB (4.3.6) [Click for support]
        /System/Library/Extensions
    [not loaded]    com.paceap.kext.pacesupport.master (5.9.1 - SDK 10.6) [Click for support]
        /System/Library/Extensions/PACESupportFamily.kext/Contents/PlugIns
    [not loaded]    com.paceap.kext.pacesupport.leopard (5.9.1 - SDK 10.4) [Click for support]
    [not loaded]    com.paceap.kext.pacesupport.panther (5.9.1 - SDK 10.-1) [Click for support]
    [loaded]    com.paceap.kext.pacesupport.snowleopard (5.9.1 - SDK 10.6) [Click for support]
    [not loaded]    com.paceap.kext.pacesupport.tiger (5.9.1 - SDK 10.4) [Click for support]
Startup Items: ℹ️
    HP IO: Path: /Library/StartupItems/HP IO
    Startup items are obsolete in OS X Yosemite
Launch Daemons: ℹ️
    [loaded]    com.adobe.fpsaud.plist [Click for support]
    [loaded]    com.disc-soft.DAEMONTools.PrivilegedHelper.plist [Click for support]
    [loaded]    com.microsoft.office.licensing.helper.plist [Click for support]
    [running]    com.paceap.eden.licensed.plist [Click for support]
    [loaded]    com.rockysandstudio.WUHelper.plist [Click for support]
    [not loaded]    org.virtualbox.startup.plist [Click for support]
    [loaded]    PACESupport.plist [Click for support]
User Launch Agents: ℹ️
    [loaded]    com.adobe.ARM.[...].plist [Click for support]
    [loaded]    com.google.keystone.agent.plist [Click for support]
    [running]    com.spotify.webhelper.plist [Click for support]
    [not loaded]    org.virtualbox.vboxwebsrv.plist [Click for support]
User Login Items: ℹ️
    uHD-Agent    UNKNOWN  (missing value)
    iTunesHelper    Application  (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
    VMware Fusion Start Menu    Application  (/Applications/VMware Fusion.app/Contents/Library/VMware Fusion Start Menu.app)
    Dropbox    Application  (/Applications/Dropbox.app)
    Google Chrome    Application Hidden (/Applications/Google Chrome.app)
    iprint-listener    Application  (/Library/Application Support/Novell/iPrint/iprint-listener.app)
    iprint-listener-gui    Application  (/Library/Application Support/Novell/iPrint/iprint-listener-gui.app)
Internet Plug-ins: ℹ️
    JavaAppletPlugin: Version: 15.0.0 - SDK 10.10 Check version
    Default Browser: Version: 600 - SDK 10.10
    AdobeAAMDetect: Version: AdobeAAMDetect 1.0.0.0 - SDK 10.6 [Click for support]
    FlashPlayer-10.6: Version: 17.0.0.169 - SDK 10.6 [Click for support]
    AdobePDFViewerNPAPI: Version: 11.0.10 - SDK 10.6 [Click for support]
    iPrint: Version: Unknown - SDK 10.7 [Click for support]
    Flash Player: Version: 17.0.0.169 - SDK 10.6 [Click for support]
    QuickTime Plugin: Version: 7.7.3
    Silverlight: Version: 5.1.20125.0 - SDK 10.6 [Click for support]
    SharePointBrowserPlugin: Version: 14.3.2 - SDK 10.6 [Click for support]
    AdobePDFViewer: Version: 11.0.10 - SDK 10.6 [Click for support]
    DirectorShockwave: Version: 12.0.2r122 - SDK 10.6 [Click for support]
User internet Plug-ins: ℹ️
    BlueStacks Install Detector: Version: Unknown
    Google Earth Web Plug-in: Version: 7.1 [Click for support]
3rd Party Preference Panes: ℹ️
    Flash Player  [Click for support]
Time Machine: ℹ️
    Time Machine not configured!
Top Processes by CPU: ℹ️
         8%    Dropbox
         4%    WindowServer
         1%    Google Chrome Helper(9)
         1%    DashboardClient(2)
         0%    taskgated
Top Processes by Memory: ℹ️
    877 MB    Google Chrome Helper(9)
    718 MB    kernel_task
    393 MB    mdworker(12)
    270 MB    Finder
    164 MB    Google Chrome
Virtual Memory Information: ℹ️
    3.17 GB    Free RAM
    4.83 GB    Used RAM
    0 B    Swap Used
Diagnostics Information: ℹ️
    Apr 20, 2015, 09:50:03 AM    /Users/[redacted]/Library/Logs/DiagnosticReports/Spotify Helper_2015-04-20-095003_[redacted].crash
    Apr 20, 2015, 09:49:47 AM    /Users/[redacted]/Library/Logs/DiagnosticReports/cloudpaird_2015-04-20-094947_[ redacted].crash
    Apr 20, 2015, 09:20:31 AM    Self test - passed
    Apr 19, 2015, 11:33:17 PM    /Users/[redacted]/Library/Logs/DiagnosticReports/Spotify Helper_2015-04-19-233317_[redacted].crash
    Apr 19, 2015, 11:32:59 PM    /Library/Logs/DiagnosticReports/Google Chrome_2015-04-19-233259_[redacted].hang
    Apr 19, 2015, 11:32:54 PM    /Library/Logs/DiagnosticReports/Spotify_2015-04-19-233254_[redacted].hang
    Apr 18, 2015, 07:36:12 PM    /Users/[redacted]/Library/Logs/DiagnosticReports/SketchUp_2015-04-18-193612_[re dacted].crash
    Apr 17, 2015, 05:59:27 PM    /Users/[redacted]/Library/Logs/DiagnosticReports/garcon_2015-04-17-175927_[reda cted].crash

Answer 1

The startup drive is failing, or there is some other internal hardware fault. If you don't already have a complete, up-to-date backup, do not try to repair the volume. Repairing it is a waste of time in any case.
Back up all data on the drive immediately if you don't already have a current backup. There are ways to back up a computer that isn't fully functional—ask if you need guidance.
Make a "Genius" appointment at an Apple Store, or go to another authorized service provider.
If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.
Keeping your confidential data secure during hardware repair
Apple also recommends that you deauthorize a device in the iTunes Store before having it serviced.
*An SSD doesn't need to be zeroed.