Latest version NOT working with El Capitan Public Beta

I also got this problem and can't reinstall

Same with me.  Installed yesterday and to my dismay found that Sophos stopped functioning.  Sophos is a great free product and I hope that it will be fully operational when El Capitan goes live.

 Any chance to Beta test Sophos as well?? 

Hi Infectious,

Sorry to hear you're having trouble, but you're unfortuantely you're right. SAV currently *should* work if it's already installed prior to your upgrade to the beta, but doing a fresh install on El Capitain is expected to fail.

We're currently working on a new release, which will be available prior to the full release of El Capitain later this fall. 

While Sophos AV appeared to continue to work on El Capitan public beta, after some hours I came back to my Mac Pro to find a message box stating that there was an error, that Sophos was not running.

I got into the console and did a search for "Sophos" and found the following messages, which may or may not be of use:

7/10/15 7:36:56.568 AM SophosConfigD[220]: WARNING: The Gestalt selector gestaltSystemVersion is returning 10.9.0 instead of 10.11.0. This is not a bug in Gestalt -- it is a documented limitation. Use NSProcessInfo's operatingSystemVersion property to get correct system version number.
Call location:
7/10/15 7:36:56.569 AM SophosConfigD[220]: 0   CarbonCore                          0x9b925933 ___Gestalt_SystemVersion_block_invoke + 135
7/10/15 7:36:56.569 AM SophosConfigD[220]: 1   libdispatch.dylib                   0x9bcdef6f _dispatch_client_callout + 50
7/10/15 7:36:56.569 AM SophosConfigD[220]: 2   libdispatch.dylib                   0x9bcdee4b dispatch_once_f + 78
7/10/15 7:36:56.569 AM SophosConfigD[220]: 3   libdispatch.dylib                   0x9bcdefb6 dispatch_once + 31
7/10/15 7:36:56.570 AM SophosConfigD[220]: 4   CarbonCore                          0x9b8a15c6 _Gestalt_SystemVersion + 1047
7/10/15 7:36:56.570 AM SophosConfigD[220]: 5   CarbonCore                          0x9b8a06f5 Gestalt + 154
7/10/15 7:36:56.570 AM SophosConfigD[220]: 6   SophosConfigD                       0x00018d14 -[NSProcessInfo(Extensions) operatingSystemVersion] + 110
7/10/15 7:39:44.175 AM com.apple.xpc.launchd[1]: (com.sophos.configuration) This service is defined to be constantly running and is inherently inefficient.
7/10/15 7:39:48.607 AM com.apple.xpc.launchd[1]: (com.sophos.uiserver) This service is defined to be constantly running and is inherently inefficient.
7/10/15 7:39:49.240 AM com.apple.xpc.launchd[1]: (com.sophos.notification) This service is defined to be constantly running and is inherently inefficient.
7/10/15 7:39:49.256 AM com.apple.xpc.launchd[1]: (com.sophos.autoupdate) This service is defined to be constantly running and is inherently inefficient.
7/10/15 7:39:49.276 AM com.apple.xpc.launchd[1]: (com.sophos.intercheck) This service is defined to be constantly running and is inherently inefficient.
7/10/15 7:39:49.298 AM com.apple.xpc.launchd[1]: (com.sophos.scan) This service is defined to be constantly running and is inherently inefficient.
7/10/15 7:39:50.034 AM SophosAutoUpdate[418]: objc[418]: Class SAVCFReadStreamPersistentThreadManager is implemented in both /Library/Sophos Anti-Virus/Libraries/libSULObjC.dylib and /Library/Sophos Anti-Virus/SophosAutoUpdate.app/Contents/MacOS/SophosAutoUpdate. One of the two will be used. Which one is undefined.
7/10/15 7:39:50.034 AM SophosAutoUpdate[418]: objc[418]: Class SAVCFReadStream is implemented in both /Library/Sophos Anti-Virus/Libraries/libSULObjC.dylib and /Library/Sophos Anti-Virus/SophosAutoUpdate.app/Contents/MacOS/SophosAutoUpdate. One of the two will be used. Which one is undefined.
7/10/15 7:39:51.256 AM SophosAutoUpdate[418]: AlreadyRegistered
7/10/15 7:39:59.000 AM kernel[0]: Sophos Anti-Virus on-access kext activated
7/10/15 7:40:46.701 AM WindowServer[211]: disable_update_timeout: UI updates were forcibly disabled by application "SophosUIServer" for over 1.00 seconds. Server has re-enabled them.
7/10/15 7:40:48.113 AM SophosConfigD[224]: WARNING: The Gestalt selector gestaltSystemVersion is returning 10.9.0 instead of 10.11.0. This is not a bug in Gestalt -- it is a documented limitation. Use NSProcessInfo's operatingSystemVersion property to get correct system version number.
Call location:
7/10/15 7:40:48.428 AM SophosConfigD[224]: 0   CarbonCore                          0x9b925933 ___Gestalt_SystemVersion_block_invoke + 135
7/10/15 7:40:48.428 AM SophosConfigD[224]: 1   libdispatch.dylib                   0x9bcdef6f _dispatch_client_callout + 50
7/10/15 7:40:48.428 AM SophosConfigD[224]: 2   libdispatch.dylib                   0x9bcdee4b dispatch_once_f + 78
7/10/15 7:40:48.428 AM SophosConfigD[224]: 3   libdispatch.dylib                   0x9bcdefb6 dispatch_once + 31
7/10/15 7:40:48.428 AM SophosConfigD[224]: 4   CarbonCore                          0x9b8a15c6 _Gestalt_SystemVersion + 1047
7/10/15 7:40:48.428 AM SophosConfigD[224]: 5   CarbonCore                          0x9b8a06f5 Gestalt + 154
7/10/15 7:40:48.428 AM SophosConfigD[224]: 6   SophosConfigD                       0x00079d14 -[NSProcessInfo(Extensions) operatingSystemVersion] + 110
7/10/15 7:40:50.021 AM WindowServer[211]: common_reenable_update: UI updates were finally reenabled by application "SophosUIServer" after 4.32 seconds [0.23fps] (server forcibly re-enabled them after 1.00 seconds [1.00fps])
7/10/15 7:40:56.763 AM SophosUIServer[555]: Bartender: Loaded BartenderHelperNinety
7/10/15 8:17:21.120 AM InstallHelper[863]: SophosAutoUpdate: Starting installation
7/10/15 8:17:21.120 AM InstallHelper[863]: SophosAutoUpdate: Installation Deployer
7/10/15 4:08:05.562 PM WindowServer[211]: disable_update_timeout: UI updates were forcibly disabled by application "SophosUIServer" for over 1.00 seconds. Server has re-enabled them.
7/10/15 4:08:08.596 PM WindowServer[211]: common_reenable_update: UI updates were finally reenabled by application "SophosUIServer" after 4.03 seconds [0.25fps] (server forcibly re-enabled them after 1.00 seconds [1.00fps])

For what it is worth, this is my system configuration:

Hardware Overview:

  Model Name:    Mac Pro
  Model Identifier:    MacPro5,1
  Processor Name:    6-Core Intel Xeon
  Processor Speed:    3.46 GHz
  Number of Processors:    1
  Total Number of Cores:    6
  L2 Cache (per Core):    256 KB
  L3 Cache:    12 MB
  Memory:    24 GB
  Processor Interconnect Speed:    6.4 GT/s
  Boot ROM Version:    MP51.007F.B03
  SMC Version (system):    1.39f11
  SMC Version (processor tray):    1.39f11
  Serial Number (system):    H01180X7EUG
  Serial Number (processor tray):    J511000SSCZJC     
  Hardware UUID:    8952E680-DEFD-5D14-B51F-C7CF6412B0A6

Note:  The 3.46GHz 6-Core Intel Xeon was an upgrade that I did.  It's been rock-solid since I did the upgrade -- which was well over a year ago.

-- Fred

Hope  we can get the update version recently.....

It looks like a may be in the same boat. Is anyone else having trouble installing a different anti virus program after previously having sophos installed?