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'Computer Won't Sleep after Text Edit in Illustrator' has been merged into this idea

CEPHtmlEngine keeps macOS awake

CEPHtmlEngine erroneously keeps macOS awake by setting PreventUserIdleSystemSleep

See details below, CEPHtmlEngine is unnecessarily keeping macOS awake using the power management API and asserting PreventUserIdleSystemSleep, on this device it has been asserting and renewing its assertion for 170 hours.

This presents a massive physical security risk to enterprise customers as it defeats IT controlled sleep/screensaver/walkaway preferences to lock the computer.

nick@Nicholass-MacBook-Pro ~ % pmset -g assertions
2025-04-29 17:49:04 -0400
Assertion status system-wide:
BackgroundTask 0
ApplePushServiceTask 0
UserIsActive 1
PreventUserIdleDisplaySleep 1
PreventSystemSleep 0
ExternalMedia 0
PreventUserIdleSystemSleep 1
NetworkClientActive 0
Listed by owning process:
pid 515(powerd): [0x00071b6c00019d4e] 00:04:13 PreventUserIdleSystemSleep named: "Powerd - Prevent sleep while display is on"

pid 54064(CEPHtmlEngine): [0x000166200005a544] 170:43:06 NoDisplaySleepAssertion named: "Video Wake Lock"

pid 962(WindowServer): [0x00071c6200099e21] 00:00:00 UserIsActive named: "com.apple.iohideventsystem.queue.tickle serviceID:10005e0bf service:AppleHIDKeyboardEventDriverV2 product:Apple Internal Keyboard / Trackpad eventType:3"

Timeout will fire in 120 secs Action=TimeoutActionRelease
No kernel assertions.

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Nick McDonald shared this idea  ·   ·  Report…  ·  Admin →
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  • Chris Woodfield commented  ·   ·  Report

    This still appears to be an issue running Illustrator 30.1 on MacOS Tahoe 26.1 Display does auto-lock and the OS doesn't go to sleep unless I close the laptop lid.

    Interestingly, looking at Activity Monitor now, I see that it's the main Adobe Illustrator process that has the Preventing Sleep flag, while the CEPHTMLEngine and related processes do not (see screenshots). This is different from what I observed when first troubleshooting this.

  • RV commented  ·   ·  Report

    Dear Adobe Support Team,

    I am writing to report an ongoing issue affecting macOS systems, specifically related to the background process CEPHtmlEngine, which is part of Adobe Creative Cloud applications.

    # Issue Overview

    On macOS, CEPHtmlEngine consistently prevents the system from entering sleep mode, even after all Adobe applications have been closed. This results in increased battery drain, unnecessary energy consumption, and disruption to system workflows.

    The problem has been observed and confirmed via the Terminal command:

    pmset -g assertions
    This outputs:

    PreventUserIdleSystemSleep 1
    pid [XXXX] CEPHtmlEngine

    # Impact

    Battery Drain: On laptops, the inability to sleep drains the battery and impacts mobility.
    Thermal Load: In some cases, CEPHtmlEngine causes higher CPU usage.
    Workflow Disruption: Automated sleep schedules or energy-saving setups are affected.
    Security Concerns: Background processes persisting post-app closure may conflict with IT policies.

    # Request for Adobe

    Please investigate why CEPHtmlEngine is blocking system sleep persistently.
    Can Adobe provide an option in preferences or an update to control or disable this behavior?
    Will future updates ensure CEPHtmlEngine respects macOS system sleep policies?

    # Temporary Workaround (User-Side)

    At present, users are forced to terminate the process manually via:

    killall CEPHtmlEngine
    However, this is not ideal or practical for most users

    I kindly request that this issue be escalated to the appropriate development team for review and resolution.

    Thank you for your attention,

  • Beardmancer commented  ·   ·  Report

    Still happening for me on macOS, Illustrator 29.4. In Activity Monitor, under the Energy tab, expanding the entry for Illustrator shows that CEPHtmlEngine is preventing sleep. It keeps my monitors on indefinitely until I quit the app.

  • Peter Hildebrandt commented  ·   ·  Report

    This problem remains. Is anyone else having problems with the sleep because of illustrator?

  • Peter Hildebrandt commented  ·   ·  Report

    Upon further checking, the problem has not been resolved. It did it again with 28.71.

  • Peter Hildebrandt commented  ·   ·  Report

    After editing the first text box in an Illustrator document, my computer will neither blank the screen nor go to sleep until Illustrator is closed. The problem started when I installed version 28.6. I am running Windows 10.

    The POWERCFG utility in Windows indicates that the offending module is CEPHtmlEngine\CEPHtmlEngine.exe. Don't know if that's helpful. See the screen capture below.

Illustrator (Desktop) Bugs: Performance

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