Gmail attachment won't download or open? Why it happens, and the fix for each cause

Cause 1: The virus scan couldn't run, or found something

Gmail scans attachments for viruses before it lets you download them. Two different things can happen here, and they need different responses.

If you see 'Gmail virus scanners are temporarily unavailable', Google says you might get this error if Gmail can't scan certain files at the moment. Nothing has been found. Google's advice is to try downloading the attachment later, or open the attachment at your own risk. Waiting a little and trying again is the safe option, and it usually works.

If Gmail actually finds a virus, the rules are firm. A message with a known virus sent to you is rejected and the sender is told, so it never reaches your inbox. If Gmail finds a virus in an attachment on an email that is already in your inbox, Google says you won't be able to download the attachment. There is no setting to override that, and you shouldn't look for one. Ask the sender to check the file on their side and send a clean copy.

Cause 2: The file is flagged as possibly dangerous or can't be scanned

Some files Gmail can't fully check, so it shows a warning instead of quietly letting you open them. Google's attachment help lists three kinds:

• Files with unverified scripts. The warning says Gmail can't confirm that the message's attachments are safe to open.
• Encrypted files. Google says some attachments, like documents that require a password to open, are encrypted and can't be scanned for viruses.
• Attached emails (.eml files). Gmail can't confirm that the sender in the .eml file actually sent those emails.

Should you open a flagged file?

What to do depends on whether you were expecting the file. Google's guidance is that if you know and trust the sender, you can ignore the warning. A password-protected invoice from your accountant that they told you about on the phone is a fair example. If you weren't expecting it, or the message looks off, Google says don't reply and don't download the attachment, and report it as spam or abuse. A surprise 'invoice' that needs a password is a classic way to sneak something past a virus scanner.

If you trust the file but still can't open it after downloading, check you have the password, and that the program it needs is installed on your computer.

Cause 3: The sender used confidential mode

If the download icon is simply missing and the email mentions an expiry date or asks for a passcode, the sender turned on confidential mode. Google's help is direct about it: if the sender turned on confidential mode, you won't be able to copy or download the message text and attachments. Printing and forwarding are switched off too.

You can still view the message and its attachments until the expiration date the sender chose, or until they remove access. If it asks for a passcode, the sender chose SMS passcode, and it goes to the phone number they entered for you. If you don't use Gmail, the passcode arrives by email.

If you need a copy you can keep, you have to ask the sender. If the message no longer opens, Google suggests contacting the sender to extend the time or send it again.

Cause 4: The 'attachment' is really a Google Drive link

Personal Gmail accounts can send attachments up to 25 MB. When a sender goes over that, Gmail removes the attachment and adds it as a Google Drive link instead. On work and school accounts, the Google Workspace administrator sets both the sending and the receiving limits, so the cut-off can be different.

That link is not a file in your email. It points to a file in the sender's Drive, and Drive's sharing rules decide who can open it. Gmail checks whether recipients have access before the email goes out and prompts the sender to change the sharing settings if they don't. If the file still ended up private, Google says you can't see it if you don't have a Google Account, if your address isn't a Google account, or if the email reached you through a mailing list. On work or school accounts, only people with a Google Account can see Drive files attached in Gmail.

• Make sure you are signed in to the Google account the email was sent to, not a different one in the same browser.
• If you see a request-access page, ask the sender to share the file with the address you actually use.
• Or ask them to set the file to 'Anyone with the link', which Google says lets recipients open it without a Google Account.

Cause 5: Your browser or an extension is blocking it

When there is no warning at all and the click just does nothing, the problem is nearly always on your computer. Google's help says to try its steps in order; the first four below cover them, and the rest are extra checks.

• Check that you're using a supported browser. Gmail lists Chrome, Firefox, Safari and Microsoft Edge, and works best in the newest and last prior version of each.
• Make sure cookies and JavaScript are turned on. Google says any browser you use for Gmail needs both.
• Turn off your browser extensions one at a time and try the download after each. Ad blockers, privacy tools and download managers are good ones to try first.
• Clear your browser's cache and cookies, then sign in again and retry.
• Check where the file went. Your browser saves attachments to its downloads folder, so a download that seemed to do nothing may already be there.
• If a video attachment shows an error screen instead of playing, Google says to download it and open it with your device's own video player instead of the preview.
• If 'Add to Drive' fails, Google notes that some attachments can't be added to Google Drive, so use 'Download' instead.
• On an Android phone, the Gmail app saves an attachment when you open the email and tap 'Download', or tap 'Save to Drive' to put it in Drive. If that fails, try the same email in a browser on a computer to see whether the problem is the phone or the file.

Prevent it next time

Most of these problems are easier to avoid than to fix after the fact.

• Keep your browser up to date. Gmail only promises to work properly in the newest and last prior versions.
• When a warning appears, read it rather than clicking past it. It tells you which of the causes above you are dealing with.
• Ask people who send you password-protected files to tell you the password some other way, and to warn you it is coming, so the 'can't be scanned' warning doesn't catch you by surprise.
• If someone regularly sends you large files, ask them to share them with the exact Google account you sign in with, so Drive links open first time.
• Use one browser profile per Google account, so you are never looking at an email with one account and opening its Drive link with another.

If you're the one sending big files

If people struggle to open the large files you send them, OneSol Send gives them a plain download link instead, for files up to 5 GB, kept for 3 days.