New Outlook Can't Attach Files From a Network Drive: Fixes

Why can new Outlook not attach files from a network drive?#

New Outlook for Windows cannot attach files from a network drive because Microsoft lists access to files on a network share as not supported there, while classic Outlook still supports it. Copy the file to your PC and attach the copy, send a OneDrive or SharePoint link, or keep classic Outlook for this workflow.

Cannot attach files in Outlook at all? Check which client you are in first. If the attach dialog will not show your mapped drive or local network share, nothing on your machine is broken in the new client and no setting will bring the drive back. Microsoft's feature comparison between new and classic Outlook lists "Access files on network share" as available in classic and not supported in new Outlook (checked October 2026).

New Outlook for Windows is web-architected: it shares its interface with Outlook on the web instead of using the classic desktop file dialog. Microsoft documents the outcome rather than the mechanism.

A second, separately documented restriction catches people out. Microsoft KB 2918627 states that in Exchange Server and Exchange Online you cannot use Outlook on the web to access shared files through a UNC path, and calls it by design. A link to a path like \\fileserver\clients\contract.pdf does not open for anyone reading in a web client.

What works and what does not, by client#

Local files and cloud files are fine. Anything that needs the client to reach across your local network is not.

On new Outlook for Mac, Microsoft's comparison row is written for Windows. If the SMB volume is mounted in Finder, test with one small file instead of assuming.

The fix that always works: copy locally, then attach#

This is the route Microsoft's own KB points at, and it works on every account type. It costs about two minutes.

1. 1

   Open the folder in File Explorer, not in Outlook

   Go to the mapped drive, or paste the UNC path into the Explorer address bar. Explorer still reaches the share normally; only the new client's attach picker cannot.

2. 2

   Copy the file, do not move it

   Ctrl+C on the file, then paste it into a local folder. Moving it takes the document away from colleagues who expect it on the share.

3. 3

   Attach the local copy in new Outlook

   In the compose window choose Attach file, browse this computer, and pick the copy. From that point it behaves as an ordinary local attachment and the only ceiling is your provider's size limit.

4. 4

   Check you copied the current version

   A stale local copy is the real risk of this method, especially on documents several people edit. Compare the modified date against the share before you send anything contractual.

5. 5

   Delete the copy once the mail has gone

   Local copies of controlled documents are what an auditor asks about. Keep one staging folder, empty it weekly, and keep the share as the system of record.

How to link to a network folder in new Outlook#

Links are a separate limitation from attachments, and the one many searchers hit. Paste a UNC or mapped-drive path into a hyperlink in new Outlook and it is treated as a web address, so clicking it opens Edge, which cannot resolve a file path. A Microsoft Community moderator answer on Microsoft Q&A says new Outlook does not currently support inserting a true link to a file on a network drive the way classic Outlook did. A later Microsoft answer calls blocked local-file and UNC links by design and says there is no official roadmap to bring them back. These are community answers, not a product commitment, so recheck the feature comparison page before you plan around them.

What to do instead, from most to least dependable:

• Send a OneDrive or SharePoint link. This is the option Microsoft's own answers recommend, and it works for people outside your network as long as you grant access.
• Use classic Outlook for the message. Links to network paths work there, and recipients on classic can open them. The toggle is in the top-right corner of the desktop app.
• Tell colleagues the path in plain text. A path pasted as text is not a clickable link in any client, but anyone on the network can paste it into File Explorer.
• Try the Word route only for yourself. One user on Microsoft Q&A reported creating the server link in Word and dragging it into a new email. It is community-reported, not documented by Microsoft, and recipients on a web client still cannot open a UNC path.

If classic Outlook also does not show the drive#

People searching this often say "I did that and it didn't work" after trying classic Outlook too. If your drive is visible in File Explorer but not in the classic attach dialog, look at how Outlook was started. Drive mappings belong to a logon session, and Microsoft documents that an app running elevated (Run as administrator) can fail to see drive letters mapped in your normal session, because the mappings do not carry across. Close Outlook and open it normally, or map the drive again in the elevated session.

Microsoft's article on this also describes the EnableLinkedConnections registry setting. It is an administrator change that needs a restart, so ask IT rather than editing the registry yourself. If the drive does not appear in File Explorer either, the problem is the mapping or the network, not Outlook.

Your options compared#

Which route fits depends less on the file than on who owns the rules about where that file may live. For some readers two of these are not permitted.

"Just put it in SharePoint" is real advice, and it is not free#

Moving the share into SharePoint or OneDrive fixes this and several adjacent problems: version history, links instead of 40 MB attachments, access from a phone. If your organisation is heading there anyway, this is a reason to go sooner.

But it is a migration, not a workaround. Folder structures rarely survive the move unchanged, permissions have to be rebuilt against groups instead of NTFS, and external sharing runs into your tenant's policy. Applications that write to a UNC path, such as practice management, CAD, accounting exports and scanners that drop PDFs onto a share, keep writing there wherever your email workflow lives.

Some files may not go at all. Regulated and client-confidential material sometimes sits on-premises by contract or policy. If that describes yours, treat the local-copy route and classic Outlook as the two real options.

When staying on classic Outlook is the right answer#

If your business runs an on-prem file server and a large part of the day is open the share, attach the file, send it, keep classic Outlook for that work. That is a fit judgement, not procrastination: the workflow exists in one client and not the other.

You have room to decide calmly. Microsoft's migration guide says existing classic Outlook installs, through perpetual and subscription licensing, will continue to be supported until at least 2029. The same architecture that removes network-share attachments also removes COM add-ins, VBA macros and custom forms; see COM add-ins in new Outlook. Not sure whether to move at all? Read should you switch to new Outlook, and if you have already switched, how to switch back to classic Outlook.

One date deserves a diary entry for admins. Enterprise opt-out, where new Outlook becomes the default for enterprise tenants and users can still switch back, is reported as 1 March 2027 in message centre post MC949965. Message centre posts are tenant-scoped and are not on Microsoft Learn, so confirm the date in your own admin centre before you plan around it.

• Stay on classic if attaching from a share is a daily, non-negotiable step and the files cannot be copied off it.
• Stay on classic if COM add-ins, macros or custom forms are also in your critical path.
• Switch if your documents already live in SharePoint, OneDrive or Teams, where a link beats an attachment anyway.
• Switch if the share is occasional, and use one staging folder for the times it comes up.
• Either way, put a quarterly reminder in the calendar to re-check the feature comparison page.

Where AI Emaily fits, and where it does not#

We build AI Emaily, so weigh this accordingly: it is a web-architected client too, and attaching directly from \\server\share is not a problem we claim to solve. Copying the file locally is what we would tell our own users to do. What AI Emaily does is the part after the attachment: triage, thread summaries and drafts written in the voice you set in your Personal Context, with approval before send in Copilot mode. See the AI email assistant and composer tools.

The short version#

New Outlook cannot attach from a network drive or link to a network folder because it is a web-architected client, and Microsoft lists network-share access as not supported rather than upcoming. Copy the file locally and attach the copy, or send a OneDrive or SharePoint link if your documents live there.

If the share is your system of record and always will be, keep classic Outlook for that workflow. It is supported until at least 2029, and choosing it deliberately beats fighting a client that was never built to reach your file server.