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Kyle_L_
Kyle_L_
Participating Frequently
February 16, 2026
Question

Unsigned File in Recent Adobe Acrobat Update

  • February 16, 2026
  • 2 replies
  • 36 views

Our organisation enforces application allowlisting, requiring all executable and installer files to be digitally signed.

Following a recent update to Adobe Acrobat, we identified an unsigned patch file included in the update package:

File Name: AcrobatDCx64Upd2500121184_incr.msp
File Path: C:\ProgramData\Adobe\ARM\Acrobat_25.001.21151
SHA1: d5114d4f34126233b48fe337811ffec8e26e2a0c
SHA256: 4ecb5fd87775bc0dc5c63c4d04c3e1229440a1a683f04e3d7544d868032b468b
Signature Status: Unsigned
Action Taken: Blocked

Because the file is unsigned, it was automatically blocked by our security controls.

We request that Adobe ensure all files included in future Acrobat releases and updates are digitally signed to support environments that enforce strict application control policies.

Please let us know if this unsigned file was intentional or if a corrected, signed version will be made available.

    2 replies

    Amal.
    Community Manager
    Amal.Community Manager
    Community Manager
    February 17, 2026

    Hi ​@Kyle_L_ 

     

    I have ecalated this internally to our development team and they are working on it and need more information, ould you please share :

    1. Geo-location
    2. Copy of actual file present in directory:
      C:\ProgramData\Adobe\ARM\Acrobat_25.001.21151
    3. File size

    So we can isolate the issue for the fix.

     

    ~Amal

    Kyle_L_
    Kyle_L_Author
    Participating Frequently
    February 17, 2026
    1. Australia
      2. Where can i safely upload the .msp file?
      3 size is 765,084 KB

       

    Amal.
    Community Manager
    Amal.Community Manager
    Community Manager
    February 18, 2026

    Hi ​@Kyle_L_ , You can upload the .msp file to any cloud storage of your choice and create a sharable link and share that link with us via private message. Just hover over my profile icon and you will see an envelope icon - click on that to send the private message.
    Note: Please mention the title of this thread in the subject of the private message for easy identification.

    ~Amal

    Amal.
    Community Manager
    Amal.Community Manager
    Community Manager
    February 17, 2026

    Hi there,

    Thank you for taking the time to share these details I completely understand how strict application allowlisting policies can impact update workflows, especially in controlled enterprise environments.

    From what you’ve described, the incremental patch file:

    AcrobatDCx64Upd2500121184_incr.msp
    located under:
    C:\ProgramData\Adobe\ARM\Acrobat_25.001.21151

    is being detected as unsigned and therefore blocked by your security controls.

    You’re absolutely right that in environments enforcing digital signature validation, any unsigned executable or installer component can trigger a block. That can definitely interrupt the update process and create operational friction.

    Please answer few questions to narrow this down:

    • Are you validating signatures using Windows Explorer > Digital Signatures tab, or via a security platform / EDR tool?
    • Is the main Acrobat installer package signed correctly, and only this incremental .msp file is reported as unsigned?
    • Was this pulled via Adobe Acrobat Updater (ARM) or deployed through enterprise packaging (e.g., SCCM / Intune / Admin Console package)?

    In most standard enterprise releases, update packages and MSP files are expected to be digitally signed. However, in some cases:

    The outer wrapper is signed but internal payload files may not individually carry a signature.

    Security tools may flag a file as unsigned if signature validation fails due to certificate chain trust issues or inspection timing during extraction.

    That said, your SHA1/SHA256 details are very helpful. Since this impacts enterprise deployment and compliance posture. I have shared this internally with our development team for further checking.

    Also you may raise this formally through Adobe Enterprise Support (Please reachout to your IT admin and ask them to raise the tiket via their admin console).

     

    Thanks again for documenting the issue so clearly.

     

    Regards

    Amal

    Kyle_L_
    Kyle_L_Author
    Participating Frequently
    February 17, 2026

    Thanks Amal!

    Ill get the IT admin to raise an enterprise support ticket as well.

    Are you validating the signatures using Windows Explorer (Digital Signatures tab) or through a security platform / EDR tool?
    We are using Windows Defender Application Control (WDAC) for validation.

    Is the main Acrobat installer package properly signed, with only the incremental .msp file being reported as unsigned?
    The software is deployed via Intune, which uses the Trusted Installer process to establish trust for the installed files.

    Was the update pulled through Adobe Acrobat Updater (ARM), or was it deployed through enterprise packaging (e.g., SCCM, Intune, or Adobe Admin Console)?
    The base installation was deployed through Intune (trusted install). However, the issue occurs when the Adobe Acrobat Updater (ARM) component attempts to apply updates, and that process is failing.

    L
    LeoUpdaterX
    Participating Frequently
    February 17, 2026

    Hi Kyle,

    ARM downloads this file from the path below-

    https://ardownload3.adobe.com/pub/adobe/acrobat/win/AcrobatDC/2500121184/AcrobatDCx64Upd2500121184_incr.msp

    You can download and compare files, including size and digital signature.

    I checked just now and did not find any issues with digital signature.

    Post download ARM validates digital signature several times and will not try to process invalid file.

    Can you also please clarify “the issue occurs when the Adobe Acrobat Updater (ARM) component attempts to apply updates, and that process is failing”

    Is it ARM failure or your validation program prevents ARM from processing update?

    Finally, it would also help if you could enable ARM verbose logging (search for iLogLevel registry value, it was posted many times here in this forum) and provide all available log files that have AdobeARM.. in the file name from the User Temp and Windows Temp folders after update is finished?

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