When configuring an e-mail attachment in K2 that contains Microsoft Office files, attempting to open these attachments from the resulting e-mail might result in an error due to the file attachments being blocked. This can occur with various versions of Microsoft Office.

Error Scenario

  1. Design a K2 workflow.
  2. Add an e-mail event to the process.
  3. Configure the e-mail event to include a Microsoft Office file as an attachment, such as a Word, Excel or PowerPoint file.
  4. Deploy the workflow.
  5. Start an instance of the workflow.
  6. Open the e-mail received.
  7. Open the file attachment.
  8. One or more errors occur and you cannot open the attachment.

Error Messages

The error messages that might occur will be similar to the following (see images below):

Error when opening a Microsoft Word attachment


Error when opening a Microsoft Excel attachment


Error when opening a Microsoft PowerPoint attachment





There are two possible solutions to work around these errors when opening Microsoft Office file attachments.  Option 1 is the longer term solution and prevents these errors from occurring again.  Option 2 is a short term solution for the specific attachment that is blocked.  Option 2 needs to be repeated every time such an attachment exists in an e-mail. Select one of the following options and follow the instructions:

Option 1

  • To unblock attachments, open the Microsoft Office program associated with the file type that is blocked.
  • Open the Trust Center by navigating to File > Options, and then select Trust Center on the left side of the Options dialog.
  • Click the Trust Center Setting button.
  • Select Protected View on the left side of the Trust Center dialog.
  • Unmark the Enable Protected View for Outlook attachments as shown below:


  • Click OK, and then OK again, and close the Office application.
  • Start a new instance of the K2 Workflow containing the e-mail event.
  • Open the Office file attachment from the e-mail.
  • Repeat this for each type of Office file that you may receive from the workflow e-mail.

Note: This setting can be modified via group policy.

Once the file type is unblocked you will see a dialog similar to the following when opening the attachments.


Option 2

  •  Open the e-mail containing the file attachment.
  • Save the file attachment to disk.
  • Locate the file attachment and right-click on it.
  • Select Properties.
  • Unblock the file by selecting the “Unblock” button (see image below).
  • The file can now be opened.


Note: It is recommended that the instructions from Option 1 are followed to ensure that all attachments can be opened in the future.