Untrusted PDF file is taking time to open

New Here ,
Jan 28, 2020

Copy link to clipboard


We are running the latest patched versions of the following

  • Windows 10 1809 OS Build 17763.914
  • Office 2016 Professional Plus 32 Bit 16.0.4266.1001
  • Adobe Acrobat Reader DC Version 2019.021.20058


The problem affects all documents that Windows decides have come from untrusted sources- eg files from Internet, email and even network drives. These files can be identified in file properties as below.


When a user tries to open an untrusted pdf, docx or xlsx files, Protected View should engage with standard office and acrobat security settings in place.


the user will experience a 5-10 minute delay in opening these documents, the application will freeze and will not open any document for this duration



We have managed to put a workaround in place disabling the Acrobat Secure app container using this reg key Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Adobe\Acrobat Reader\DC\FeatureLockDown\"bEnableProtectedModeAppContainer"  = 0 (default is 1) and also by disabling the Protected View Features in Office as necessary to keep some users working but this is a significant compromise to our security profile and we need to revert those changes asap.

Crash or freeze







Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more

Have something to add?

Join the conversation