*** Panic Report ***What does this mean?

My iMac is randomly going black and restarting. I used EtreCheck and pasted the report below as well as the *** Panic Report ***

How can I make this random restarting stop??

EtreCheck version: 2.9.12 (265)

Report generated 2016-06-21 11:31:37

Download EtreCheck from https://etrecheck.com

Runtime 8:00

Performance: Below Average

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

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

Problem: Computer is restarting

Hardware Information:ⓘ

iMac (27-inch, Mid 2011)

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

iMac - model: iMac12,2

1 3.1 GHz Intel Core i5 CPU: 4-core

8 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

Empty

BANK 1/DIMM1

Empty

Bluetooth: Old - Handoff/Airdrop2 not supported

Wireless: en1: 802.11 a/b/g/n

Video Information:ⓘ

AMD Radeon HD 6970M - VRAM: 1024 MB

iMac 2560 x 1440

System Software:ⓘ

OS X El Capitan 10.11.5 (15F34) - Time since boot: less than an hour

Disk Information:ⓘ

ST31000528AS disk0 : (1 TB) (Rotational)

EFI (disk0s1) /Volumes/firmwaresyncd.5JrmsV : 210 MB (191 MB free)

Macintosh HD (disk0s2) / : 999.35 GB (605.76 GB free)

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

HL-DT-STDVDRW GA32N ()

USB Information:ⓘ

Apple Inc. FaceTime HD Camera (Built-in)

Apple, Inc. Keyboard Hub

Apple Inc. Apple Keyboard

Apple Inc. BRCM2046 Hub

Apple Inc. Bluetooth USB Host Controller

Seagate BUP Slim SL 2 TB

EFI (disk1s1) <not mounted> : 210 MB

BACKUP (disk1s2) /Volumes/BACKUP : 2.00 TB (861.54 GB free)

Apple Computer, Inc. IR Receiver

Apple Card Reader

Thunderbolt Information:ⓘ

Apple Inc. thunderbolt_bus

Gatekeeper:ⓘ

Mac App Store and identified developers

Kernel Extensions:ⓘ

/Library/Extensions

[loaded] net.telestream.driver.TelestreamAudio (1.1.1 - SDK 10.8 - 2016-06-11) [Support]

/System/Library/Extensions

[not loaded] com.dymo.usbprinterclassdriver.kext (1.0 - 2016-06-11) [Support]

[not loaded] com.pctools.iantivirus.kfs (1.0.1 - 2016-06-11) [Support]

[not loaded] com.seagate.driver.PowSecDriverCore (5.0.1 - 2016-06-11) [Support]

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

[not loaded] com.seagate.driver.PowSecLeafDriver_10_4 (5.0.1 - 2010-10-19) [Support]

[not loaded] com.seagate.driver.PowSecLeafDriver_10_5 (5.0.1 - 2010-10-19) [Support]

[not loaded] com.seagate.driver.SeagateDriveIcons (5.0.1 - 2010-10-19) [Support]

System Launch Agents:ⓘ

[not loaded] 9 Apple tasks

[loaded] 164 Apple tasks

[running] 65 Apple tasks

System Launch Daemons:ⓘ

[not loaded] 40 Apple tasks

[loaded] 162 Apple tasks

[running] 89 Apple tasks

Launch Agents:ⓘ

[loaded] com.oracle.java.Java-Updater.plist (2014-09-27) [Support]

[running] com.seagate.SeagateStorageGauge.plist (2010-03-10) [Support]

Launch Daemons:ⓘ

[loaded] bootps.plist

[loaded] com.adobe.fpsaud.plist (2016-05-09) [Support]

[loaded] com.adobe.versioncueCS4.plist (2009-11-14) [Support]

[not loaded] com.danga.memcached.plist

[loaded] com.microsoft.office.licensing.helper.plist (2012-11-05) [Support]

[loaded] com.oracle.java.Helper-Tool.plist (2014-09-27) [Support]

[running] com.vix.cron.plist

[loaded] exec.plist

[loaded] finger.plist

[loaded] ftp.plist

[loaded] jp.co.canon.MasterInstaller.plist (2016-05-24) [Support]

[loaded] login.plist

[loaded] ntalk.plist

[loaded] org.apache.httpd.plist

[loaded] org.cups.cups-lpd.plist

[running] org.cups.cupsd.plist

[loaded] org.net-snmp.snmpd.plist

[running] org.ntp.ntpd.plist

[loaded] org.openldap.slapd.plist

[loaded] org.postfix.master.plist

[loaded] shell.plist

[loaded] ssh.plist

[loaded] telnet.plist

[loaded] tftp.plist

User Launch Agents:ⓘ

[loaded] com.citrixonline.GoToMeeting.G2MUpdate.plist (2016-06-13) [Support]

[running] com.lastpass.LastPassHelper.plist (2016-04-13) [Support]

User Login Items:ⓘ

Dropbox Application (/Applications/Dropbox.app)

Google Chrome Application (/Applications/Google Chrome.app)

SpeechSynthesisServer Application (/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks /SpeechSynthesis.framework/Versions/A/SpeechSynthesisServer.app)

Other Apps:ⓘ

[running] com.etresoft.EtreCheck.208032

[running] com.evernote.EvernoteHelper

[running] com.getdropbox.dropbox.1952

[loaded] com.google.Chrome.60512

[loaded] 404 Apple tasks

[running] 170 Apple tasks

Internet Plug-ins:ⓘ

DirectorShockwave: 11.6.5r635 (2012-04-27) [Support]

nplastpass: 4.1.2 - SDK 10.11 (2016-04-13) [Support]

Default Browser: 601 - SDK 10.11 (2016-05-24)

AdobePDFViewerNPAPI: 11.0.07 - SDK 10.6 (2014-05-22) [Support]

FlashPlayer-10.6: 21.0.0.213 - SDK 10.6 (2016-04-13) [Support]

Silverlight: 5.1.30514.0 - SDK 10.6 (2015-01-07) [Support]

QuickTime Plugin: 7.7.3 (2016-05-24)

Flash Player: 21.0.0.213 - SDK 10.6 (2016-04-13) Outdated! Update

PepperFlashPlayer: 21.0.0.242 - SDK 10.6 (2016-05-30) [Support]

SharePointBrowserPlugin: 14.6.4 - SDK 10.6 (2016-05-16) [Support]

AdobePDFViewer: 11.0.07 - SDK 10.6 (2014-05-22) [Support]

iPhotoPhotocast: 7.0 - SDK 10.8 (2013-04-17)

JavaAppletPlugin: Java 8 Update 91 build 14 (2016-05-28) Check version

User internet Plug-ins:ⓘ

CitrixOnlineWebDeploymentPlugin: 1.0.105 (2013-04-25) [Support]

Safari Extensions:ⓘ

Buffer - Buffer - http://buffer.com (2016-04-13)

Save to Pocket - Read It Later, Inc. - http://getpocket.com/ (2016-04-13)

Clean Links for Google - Dennis Umetzu - http://www.umetzu.com (2016-05-06)

LastPass - LastPass - https://lastpass.com (2016-05-06)

Evernote Web Clipper - Evernote Corp. - http://evernote.com (2016-05-27)

Pin It Button - Pinterest, Inc. - http://www.pinterest.com/ (2016-05-06)

3rd Party Preference Panes:ⓘ

DivX (2010-08-25) [Support]

Flash Player (2016-05-09) [Support]

Flip4Mac WMV (2012-09-14) [Support]

Java (2016-05-28) [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: 393.59 GB

Destinations:

BACKUP [Local]

Total size: 2.00 TB

Total number of backups: 53

Oldest backup: 2/13/16, 12:38 AM

Last backup: 6/20/16, 6:57 PM

Size of backup disk: Adequate

Backup size 2.00 TB > (Disk used 393.59 GB X 3)

Top Processes by CPU:ⓘ

9% Google Chrome Helper(20)

3% kernel_task

2% WindowServer

1% Dropbox

0% mdworker(3)

Top Processes by Memory:ⓘ

2.37 GB Google Chrome Helper(20)

715 MB kernel_task

270 MB Google Chrome

131 MB Dropbox

98 MB mds_stores

Virtual Memory Information:ⓘ

3.03 GB Free RAM

4.97 GB Used RAM (1.81 GB Cached)

0 B Swap Used

Diagnostics Information:ⓘ

Jun 21, 2016, 11:19:59 AM /Library/Logs/DiagnosticReports/Kernel_2016-06-21-111959_[redacted].panic [Details]

Jun 21, 2016, 11:19:27 AM Self test - passed

Jun 20, 2016, 07:07:37 PM /Library/Logs/DiagnosticReports/Kernel_2016-06-20-190737_[redacted].panic [Details]

Jun 20, 2016, 02:10:54 PM ~/Library/Logs/DiagnosticReports/DocumentPopoverViewService_2016-06-20-141054_[ redacted].crash

com.apple.appkit.xpc.documentPopoverViewService - /System/Library/Frameworks/AppKit.framework/Versions/C/XPCServices/DocumentPopo verViewService.xpc/Contents/MacOS/DocumentPopoverViewService

Jun 18, 2016, 06:36:45 PM ~/Library/Logs/DiagnosticReports/ScreenSaverEngine_2016-06-18-183645_[redacted] .crash

com.apple.ScreenSaver.Engine -

/System/Library/Frameworks/ScreenSaver.framework/Resources/ScreenSaverEngine.app /Contents/MacOS/ScreenSaverEngine

Jun 11, 2016, 10:21:42 AM /Library/Logs/DiagnosticReports/Kernel_2016-06-11-102142_[redacted].panic [Details]

Jun 1, 2016, 06:35:00 PM /Library/Logs/DiagnosticReports/Kernel_2016-06-01-183500_[redacted].panic [Details]

May 30, 2016, 12:47:37 PM /Library/Logs/DiagnosticReports/Kernel_2016-05-30-124737_[redacted].panic [Details]

May 30, 2016, 11:47:25 AM /Library/Logs/DiagnosticReports/Kernel_2016-05-30-114725_[redacted].panic [Details]

May 30, 2016, 10:56:49 AM /Library/Logs/DiagnosticReports/Kernel_2016-05-30-105649_[redacted].panic [Details]

May 24, 2016, 12:57:07 PM /Library/Logs/DiagnosticReports/Kernel_2016-05-24-125707_[redacted].panic [Details]

Anonymous UUID: 598DE295-E318-081A-2E9E-96D49E2CFC96

Tue Jun 21 11:19:57 2016

*** Panic Report ***

panic(cpu 1 caller 0xffffff800a11f98b): "a freed zone element has been modified in zone kalloc.80: expected 0xdeadbeefdeadbeef but found 0xdeadbeefdeadbeed, bits changed 0x2, at offset 16 of 80 in element 0xffffff801fd5ac70, cookies 0x3f001161aa28bb38 0x535215919d8230f"@/Library/Caches/com.apple.xbs/Sources/xnu/xnu-3248.50.21/osf mk/kern/zalloc.c:503

Backtrace (CPU 1), Frame : Return Address

0xffffff81155d3270 : 0xffffff800a0dab12

0xffffff81155d32f0 : 0xffffff800a11f98b

0xffffff81155d3420 : 0xffffff800a5a22de

0xffffff81155d3460 : 0xffffff800a2e6c9a

0xffffff81155d34c0 : 0xffffff800a4fc244

0xffffff81155d35b0 : 0xffffff800a4fcb6d

0xffffff81155d3750 : 0xffffff800a4f5a95

0xffffff81155d37e0 : 0xffffff800a50fa7d

0xffffff81155d39b0 : 0xffffff800a2f2efe

0xffffff81155d3a80 : 0xffffff800a2f26a8

0xffffff81155d3bc0 : 0xffffff800a305c25

0xffffff81155d3c10 : 0xffffff800a313317

0xffffff81155d3f30 : 0xffffff800a3087fa

0xffffff81155d3f60 : 0xffffff800a6286a1

0xffffff81155d3fb0 : 0xffffff800a1ecc66

BSD process name corresponding to current thread: Dropbox

Mac OS version:

15F34

Kernel version:

Darwin Kernel Version 15.5.0: Tue Apr 19 18:36:36 PDT 2016; root:xnu-3248.50.21~8/RELEASE_X86_64

Kernel UUID: 7E7B0822-D2DE-3B39-A7A5-77B40A668BC6

Kernel slide: 0x0000000009e00000

Kernel text base: 0xffffff800a000000

__HIB text base: 0xffffff8009f00000

System model name: iMac12,2 (Mac-942B59F58194171B)

System uptime in nanoseconds: 58453196182446

last loaded kext at 420912598308: com.apple.filesystems.msdosfs 1.10 (addr 0xffffff7f8d347000, size 69632)

last unloaded kext at 505934818608: com.apple.filesystems.msdosfs 1.10 (addr 0xffffff7f8d347000, size 61440)

loaded kexts:

net.telestream.driver.TelestreamAudio 1.1.1

com.apple.driver.AppleBluetoothMultitouch 90.3

com.apple.driver.AppleHWSensor 1.9.5d0

com.apple.iokit.IOBluetoothSerialManager 4.4.5f3

com.apple.driver.AGPM 110.22.0

com.apple.driver.AudioAUUC 1.70

com.apple.driver.pmtelemetry 1

com.apple.iokit.IOUserEthernet 1.0.1

com.apple.filesystems.autofs 3.0

com.apple.driver.AppleOSXWatchdog 1

com.apple.driver.AppleMikeyHIDDriver 124

com.apple.driver.AppleMikeyDriver 274.9

com.apple.driver.AppleHDA 274.9

com.apple.driver.AppleUpstreamUserClient 3.6.1

com.apple.kext.AMDFramebuffer 1.4.2

com.apple.driver.AppleIntelHD3000Graphics 10.0.0

com.apple.Dont_Steal_Mac_OS_X 7.0.0

com.apple.AMDRadeonX3000 1.4.2

com.apple.driver.AppleBacklight 170.8.9

com.apple.driver.AppleSMCPDRC 1.0.0

com.apple.driver.AppleSMCLMU 208

com.apple.driver.AppleThunderboltIP 3.0.8

com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport 4.4.5f3

com.apple.driver.AppleMCCSControl 1.2.13

com.apple.driver.AppleLPC 3.1

com.apple.driver.ACPI_SMC_PlatformPlugin 1.0.0

com.apple.driver.AppleHV 1

com.apple.driver.AppleIntelSlowAdaptiveClocking 4.0.0

com.apple.driver.AppleIntelSNBGraphicsFB 10.0.0

com.apple.kext.AMD6000Controller 1.4.2

com.apple.iokit.SCSITaskUserClient 3.7.7

com.apple.driver.AppleUSBCardReader 3.7.1

com.apple.driver.AppleIRController 327.6

com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1

com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0

com.apple.BootCache 38

com.apple.iokit.IOAHCIBlockStorage 2.8.5

com.apple.driver.AppleFWOHCI 5.5.4

com.apple.iokit.AppleBCM5701Ethernet 10.2.0

com.apple.driver.AirPort.Atheros40 700.74.5

com.apple.driver.AppleAHCIPort 3.1.8

com.apple.driver.usb.AppleUSBEHCIPCI 1.0.1

com.apple.driver.AppleACPIButtons 4.0

com.apple.driver.AppleRTC 2.0

com.apple.driver.AppleHPET 1.8

com.apple.driver.AppleSMBIOS 2.1

com.apple.driver.AppleACPIEC 4.0

com.apple.driver.AppleAPIC 1.7

com.apple.driver.AppleIntelCPUPowerManagementClient 218.0.0

com.apple.nke.applicationfirewall 163

com.apple.security.quarantine 3

com.apple.security.TMSafetyNet 8

com.apple.driver.AppleIntelCPUPowerManagement 218.0.0

com.apple.driver.IOBluetoothHIDDriver 4.4.5f3

com.apple.driver.AppleMultitouchDriver 304.12

com.apple.driver.AppleHIDTransport 5

com.apple.iokit.IOSerialFamily 11

com.apple.iokit.IOSurface 108.2.1

com.apple.kext.triggers 1.0

com.apple.driver.DspFuncLib 274.9

com.apple.kext.OSvKernDSPLib 525

com.apple.iokit.IOAcceleratorFamily2 205.10

com.apple.driver.AppleBacklightExpert 1.1.0

com.apple.iokit.IONDRVSupport 2.4.1

com.apple.driver.CoreCaptureResponder 1

com.apple.driver.AppleSMBusPCI 1.0.14d1

com.apple.driver.AppleHDAController 274.9

com.apple.iokit.IOHDAFamily 274.9

com.apple.iokit.IOAudioFamily 204.4

com.apple.vecLib.kext 1.2.0

com.apple.driver.AppleThunderboltEDMSink 4.1.1

com.apple.iokit.IOBluetoothHostControllerUSBTransport 4.4.5f3

com.apple.iokit.IOBluetoothFamily 4.4.5f3

com.apple.driver.AppleSMBusController 1.0.14d1

com.apple.driver.AppleSMC 3.1.9

com.apple.driver.IOPlatformPluginLegacy 1.0.0

com.apple.driver.IOPlatformPluginFamily 6.0.0d7

com.apple.iokit.IOSlowAdaptiveClockingFamily 1.0.0

com.apple.iokit.IOFireWireIP 2.2.6

com.apple.kext.AMDSupport 1.4.2

com.apple.AppleGraphicsDeviceControl 3.12.8

com.apple.iokit.IOGraphicsFamily 2.4.1

com.apple.iokit.IOSCSIMultimediaCommandsDevice 3.7.7

com.apple.iokit.IOBDStorageFamily 1.8

com.apple.iokit.IODVDStorageFamily 1.8

com.apple.iokit.IOCDStorageFamily 1.8

com.apple.iokit.IOAHCISerialATAPI 2.6.2

com.apple.driver.AppleHIDKeyboard 181

com.apple.driver.usb.IOUSBHostHIDDevice 1.0.1

com.apple.iokit.IOSCSIBlockCommandsDevice 3.7.7

com.apple.iokit.IOUSBMassStorageDriver 1.0.0

com.apple.iokit.IOSCSIArchitectureModelFamily 3.7.7

com.apple.iokit.IOUSBHIDDriver 900.4.1

com.apple.driver.usb.cdc 5.0.0

com.apple.driver.usb.networking 5.0.0

com.apple.driver.usb.AppleUSBHostCompositeDevice 1.0.1

com.apple.driver.usb.AppleUSBHub 1.0.1

com.apple.driver.AppleThunderboltDPInAdapter 4.1.3

com.apple.driver.AppleThunderboltDPOutAdapter 4.1.3

com.apple.driver.AppleThunderboltDPAdapterFamily 4.1.3

com.apple.driver.AppleThunderboltPCIDownAdapter 2.0.2

com.apple.driver.AppleThunderboltNHI 4.0.4

com.apple.iokit.IOThunderboltFamily 6.0.2

com.apple.iokit.IOFireWireFamily 4.6.1

com.apple.iokit.IOEthernetAVBController 1.0.3b3

com.apple.driver.mDNSOffloadUserClient 1.0.1b8

com.apple.iokit.IO80211Family 1110.26

com.apple.iokit.IONetworkingFamily 3.2

com.apple.driver.corecapture 1.0.4

com.apple.iokit.IOUSBFamily 900.4.1

com.apple.iokit.IOAHCIFamily 2.8.1

com.apple.driver.usb.AppleUSBEHCI 1.0.1

com.apple.iokit.IOUSBHostFamily 1.0.1

com.apple.driver.AppleUSBHostMergeProperties 1.0.1

com.apple.driver.AppleEFINVRAM 2.0

com.apple.iokit.IOHIDFamily 2.0.0

com.apple.driver.AppleEFIRuntime 2.0

com.apple.iokit.IOSMBusFamily 1.1

com.apple.security.sandbox 300.0

com.apple.kext.AppleMatch 1.0.0d1

com.apple.driver.AppleKeyStore 2

com.apple.driver.AppleMobileFileIntegrity 1.0.5

com.apple.driver.AppleCredentialManager 1.0

com.apple.driver.DiskImages 417.4

com.apple.iokit.IOStorageFamily 2.1

com.apple.iokit.IOReportFamily 31

com.apple.driver.AppleFDEKeyStore 28.30

com.apple.driver.AppleACPIPlatform 4.0

com.apple.iokit.IOPCIFamily 2.9

com.apple.iokit.IOACPIFamily 1.4

com.apple.kec.pthread 1

com.apple.kec.corecrypto 1.0

com.apple.kec.Libm 1

Model: iMac12,2, BootROM IM121.0047.B23, 4 processors, Intel Core i5, 3.1 GHz, 8 GB, SMC 1.72f2

Graphics: AMD Radeon HD 6970M, AMD Radeon HD 6970M, PCIe, 1024 MB

Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1333 MHz, 0x80AD, 0x484D54333531533642465238432D48392020

Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1333 MHz, 0x80AD, 0x484D54333531533642465238432D48392020

AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x9A), Atheros 9380: 4.0.74.0-P2P

Bluetooth: Version 4.4.5f3 17904, 3 services, 27 devices, 1 incoming serial ports

Network Service: Wi-Fi, AirPort, en1

Serial ATA Device: ST31000528AS, 1 TB

Serial ATA Device: HL-DT-STDVDRW GA32N

USB Device: USB 2.0 Bus

USB Device: FaceTime HD Camera (Built-in)

USB Device: Hub

USB Device: Keyboard Hub

USB Device: Apple Keyboard

USB Device: BRCM2046 Hub

USB Device: Bluetooth USB Host Controller

USB Device: USB 2.0 Bus

USB Device: Hub

USB Device: BUP Slim SL

USB Device: IR Receiver

USB Device: Card Reader

Thunderbolt Bus: iMac, Apple Inc., 25.1