A potential cause for this error when trying to open a PDF could be that user is using a cloud storage app to sync documents or they originally downloaded the document from their cloud storage and changes were being saved to the cloud. When the connection to the cloud storage sync is disrupted, that can cause this error:
User will also be unable to upload or attach the PDF document to emails or to online portals.
First, it is recommended to test renaming the file and making a copy. If renaming the file does not work and making a copy yields this error:
Error 0x8007016A: The cloud file provider is not running
This is an indication that the issue is with the Cloud storage app sync. In this example, the issue is with the OneDrive sync. Please check to see if there is a cloud storage app icon in the taskbar at the bottom right. In this example, we see the OneDrive icon indicates that it is not connected:
This can often happen as well if the user has deleted their original Cloud storage account that was synced or migrated all the data to a new account. If the user is still using the same account and is merely not signed in, they can sign back in through the cloud storage app and wait for the app to sync back online. If the user migrated to a new account, they will need to navigate to the settings within the Cloud Storage application and add the new account.
After adding account, they will just have to sign back in:
Once signed in, they should see the cloud storage sync turn back on and they will be able to access the PDF