Creative Cloud 6.10.0.253 stuck initializing — ADS_PING_MISS / CommBridge Error 535 after clean reinstall

I'm having a persistent Creative Cloud Desktop issue on Windows 11. Creative Cloud gets stuck at “Initializing Creative Cloud…”, eventually displays “Creative Cloud is taking longer than usual to load”, and then stops with an error.

I have already performed a clean reinstall of Creative Cloud, including cleanup/reinstallation, and Photoshop and Illustrator are now installed and working. The Creative Cloud desktop application itself still will not initialize.

Current Creative Cloud version: 6.10.0.253
Windows: Windows 11, build 26200.9168

The ACC.log shows a very specific failure sequence:

• ADS is detected and launched successfully.
• Adobe Desktop Service.exe loads AdobePIM.dll.
• PIM initializes successfully.
• The PIM database reports “SUCCESS Created Tables” and “PIM Database is Up To Date.”
• Immediately afterward, Adobe's CommBridge reports:

CBRawReadTry failed for packet info

followed by:

Prior InputPipe State(1) Status:1 Error:535

and:

Post InputPipe State(0) Status:1 Error:535

Creative Cloud then reports:

ADS seems to be hanged. No response upon pinging.. ADS/Vulcan issue...Killing ADS & Vulcan

followed by:

PingMissCount crosses pingMissThreshold

PingMiss more than threshold. Looks like ADS is crashing continuously

No point in launching ADS again. Showing corruption dialog

errorType: ADS_PING_MISS

Additional testing performed:

• Adobe Desktop Service.exe exists and is version 6.10.0.253.
• Adobe Desktop Service.exe has a valid Adobe digital signature.
• AdobePIM.dll exists, is version 6.10.0.253, and has a valid Adobe signature.
• AdobePIM.dll successfully loads when tested directly from a 32-bit PowerShell process.
• ADS can be manually launched with start "" "...\Adobe Desktop Service.exe" and remains running when Creative Cloud is not attempting initialization.
• When Creative Cloud attempts initialization, ADS subsequently disappears and Creative Cloud reports the ADS_PING_MISS failure.
• AdobeIPCBroker.exe is running and reports Responding: True.
• The Adobe IPC Broker control pipe com.adobe.AdobeIPCBroker.ctrl-Andrea exists.
• Adobe named pipes are present, including multiple adobe_crclient_... pipes.
• WMI is running normally.
• UAC is enabled normally.
• No Adobe RUNASADMIN compatibility entries remain in HKLM or HKCU.
• No Adobe entries are present in the Windows HOSTS file.
• WinHTTP proxy is set to Direct access (no proxy server).
• Adobe's Adobe Native Client firewall rules are enabled and allow both inbound and outbound traffic.
• Temporarily stopping FortectNetShield made no difference to the Creative Cloud initialization failure.
• Windows Event Viewer does not show a conventional Adobe Desktop Service application crash for the failure.

My current observation: ADS itself can launch and remain alive, but when Creative Cloud attempts to communicate with it, the Adobe CommBridge/IPC communication fails with Error 535, after which CCDContainer's ADS watchdog terminates ADS and produces ADS_PING_MISS.

At this point I am specifically looking for help diagnosing the Adobe Desktop Service / CommBridge / Vulcan / IPC communication failure, rather than repeating a Creative Cloud reinstall.

What component or permission controls the InputPipe/CommBridge communication that is returning Error 535, and is there an Adobe diagnostic tool or logging option that can identify why the pipe communication is failing?