How to fix attachments not downloading on iPhone and MacBook

Attachments that appear greyed out in Outlook are typically being blocked by Outlook’s security features or by another component such as Exchange policies, antivirus, or browser/app settings.

Use these steps to narrow and fix the issue:

1. Check if Outlook is blocking the file type
   • Outlook blocks certain “unsafe” file types (for example, .exe and some database files). These will show as unavailable/greyed out and can’t be opened or saved directly.
   • If the attachment is one of these blocked types, ask the sender to:
     • Upload the file to OneDrive or another file share and send a link instead, or
     • Compress the file (for example, into a .zip) and resend it, or
     • Rename the file extension to a non-blocked type (for example, change .exe to .doc), send it, then rename it back after saving locally.
2. Use a file share or cloud link instead of direct attachment
   • Ask the sender to save the file to a server, FTP site, or OneDrive and send a link.
   • Open the link from Outlook on the iPhone or MacBook and download the file directly to the device.
3. Have the sender compress the file
   • Ask the sender to use a compression utility (such as WinZip) to create a .zip file and attach that instead.
   • Outlook does not treat common compressed formats as unsafe, so the attachment should no longer be greyed out.
4. Have the sender rename the file extension
   • If compression is not possible, the sender can rename the file to a safe extension (for example, from .exe to .doc) and resend.
   • After saving the file locally, rename it back to the original extension before opening.
5. If using an Exchange/Work account, contact the administrator
   • For work accounts, Exchange administrators can configure which attachment types are blocked.
   • If all attachments are greyed out, or important business file types (for example, .docx, .xlsx, .pdf) are blocked, contact the email administrator and request a review of the Outlook/Exchange attachment security settings for the mailbox.
6. If using Outlook on the web (OWA) on Mac
   • If attachments won’t download or preview in Outlook on the web, ensure the browser and Outlook are fully updated.
   • If the issue occurs only when accessing shared or additional mailboxes, use the full Outlook client on Mac as a workaround.

If attachments remain greyed out after these steps, the most likely cause is a server-side policy or security product (such as antivirus or VPN) enforced by the organization; in that case, the mail or security administrator must adjust those controls.

References:

• Blocked attachments in Outlook
• Outlook blocked access to the following potentially unsafe attachments
• You cannot open linked file attachments in Outlook: "Outlook blocked access to the following potentially unsafe attachments"
• Attachments can’t be downloaded or previewed from Outlook Web App
• Attachments not downloading - Microsoft Q&A
• "You don't have appropriate permission to perform this operation." message when I try and open an attachment in Outlook - Microsoft Q&A
• Error message when trying to download attachments from OWA 365 - Microsoft Q&A
• Outlook Classic "hangs" if I want to open or copy attachments - Microsoft Q&A
• Some options are grayed out in the attachment dropdown menu in legacy Outlook for Mac
• Fixes or workarounds for recent issues in Outlook for Mac