Limits
Up to 10 MB per file, 10 files and 20 MB in total on one email.
Each inbox has 100 MB of room for attachments. An incoming file that does not fit is left out and the email says so.
Drag and drop, or use the paperclip.
Files you cannot attach
Programs and scripts (such as .exe, .bat, .js, .ps1, .jar and .iso) cannot be attached or sent.
How files are checked (newer Mail)
Every file is checked as it arrives and as you attach it, in two layers:
Always, inside Rosterr: the standard antivirus test file; programs and scripts, found by name and by what is inside, so an "invoice.pdf" that is really a program is caught; and warnings for things that are fine to own but worth a pause: macros in Office files, a PDF that can run scripts or launch programs, a script inside an SVG or HTML file, a program inside a zip, and a password-protected zip (which cannot be looked inside).
With a virus scanner: if Nebula runs a virus scanner for your install, every file is also sent to it.
What you may see
What it shows | What it means |
Scanned, no virus found | The virus scanner found nothing |
(nothing) | No virus scanner is set up and the built-in checks found nothing. It downloads as normal |
Suspicious warning | Macros, scripts, a program in a zip or a password-protected zip. You are asked before downloading, and pictures are never displayed in the page |
Removed | A virus or a program. The file is not kept at all. The email says "The attachment x was removed: ..." |
Being checked | The scanner could not be reached. The file is kept but cannot be downloaded or forwarded until it has been checked |
A removed file never stops the email arriving. When you are sending, a virus, a disguised program or a file that cannot be checked is refused when you attach it ("That file was blocked: ...").
How downloads stay safe
Files always download (only plain pictures are shown in the page). They are served so they cannot run, and only to people who can read that inbox. Uploads that nobody sends, or saves in a draft, are removed after a day.
Tips
If a file is refused, put it in a zip without a password, or share it by link.
Do not open "Suspicious" files unless you expect them.
Related articles
Write, reply and forward email (undo send, send later, drafts, formatting)
Mail sending limits: how many people you can email each day
Mail troubleshooting: cannot send, not receiving, bounced email and missing attachments