Opening a file a stranger sent you is the riskiest thing a form owner does, so Maxforms checks every upload before it's ever available to download. Images are re-encoded, documents have their active content stripped, and anything that fails the check is quarantined — you can't download it, and the submission doesn't notify you. This runs on every plan and there's nothing to switch on.
What gets checked#
Three checks run automatically on every uploaded file:
- Images are decoded and written out again as a clean copy. That drops the embedded metadata and anything hidden after the end of the image data. Files with absurd pixel dimensions are rejected before they're decoded at all.
- Office documents —
.docx,.xlsx,.pptxand their OpenDocument equivalents — have their macro, OLE, and ActiveX parts removed. A document that points at an external template or object is rejected outright, because removing a part can't neutralise a payload that's fetched from somewhere else. The file you download afterwards is the real document, minus the parts that could run code. - PDFs are inspected for actions that run the moment the file is opened. A PDF carrying one — or an encrypted PDF whose contents can't be inspected — is rejected. A clean PDF is passed through untouched.
The check is signature-independent: it doesn't need to recognise a specific piece of malware to defuse it.
What you'll see#
Almost always, nothing. The check runs in the background within seconds of the response arriving, and by the time you open the submission the file is there as a normal download link.
When a file isn't available, Maxforms says so in place of the file name, on both the Submissions table and the submission detail:
- Scanning… — the check is still running. Refresh in a moment.
- Quarantined — blocked by safety scan — the file failed. There's no download link, on purpose.
Both appear with a shield icon rather than the usual download arrow.
If a file is quarantined#
The file isn't recoverable from inside Maxforms. There's no override, no "download anyway", and no way to run the check again — that's deliberate, because the alternative is a one-click path to opening the exact file the system decided not to trust.
The rest of the submission is unaffected: every other answer is readable, and the response counts normally. If you need what was in that file, ask the person to send it again, ideally in a different format — a PDF exported flat, or an image rather than a document.
Quarantine also holds back the submission's notifications. If you're expecting an email about a response and it never came, and its file shows one of those two labels, that's why.
Download links expire#
Files aren't served from a public address. Every download link is signed and time-limited:
- In the app — links last about an hour from when the page loaded. If a download fails on a page you left open, reload the submission and try again.
- In notification emails and PDF copies — links last 7 days, because email gets read days later. After that, open the submission in Maxforms to download the file.
Links always download the file rather than opening it in your browser.
Storage and how long files are kept#
Uploads count toward your workspace's file storage allowance — 1 GB on Free, 50 GB on Pro, and 250 GB on Business and the nonprofit plan.
An uploaded file lives as long as the submission it belongs to. Delete the submission and it goes to the workspace Trash, where it can be restored for 30 days before it and its files are erased for good — see Trash and recovery. Files someone started uploading but never submitted are cleared out after 24 hours.
What you control#
The safety checks aren't configurable, but what people are allowed to send is. On the File Upload field you set Maximum file size (MB), which Allowed file types you accept, and whether several files are allowed at once. Narrowing the accepted types is the single most effective thing you can do — if you only need photos, don't accept documents. See Collect file uploads.
What respondents see#
Nothing about the checks. Uploading and submitting works the same way regardless, and the person who filled in your form isn't told if their file is later quarantined.
If a file has said "Scanning…" for a long time#
Give it a few minutes and reload — almost every check finishes in seconds. Checks that never finish are quarantined automatically rather than being left hanging, so a file stuck in this state will end up showing Quarantined — blocked by safety scan instead, though that backstop can take up to a couple of hours to fire. If a file you're sure about ends up there, email [email protected] with the form name and the submission number.
If uploads stop being accepted#
Your workspace may have hit its file storage allowance. Check Settings → Billing, then either delete old submissions with large attachments — remembering that trashed items hold their storage until they're erased — or move up a plan. See Change your plan and manage billing.