Thunderbird
Close matchFreeFree, handles several accounts in one window, and has the unified inbox Mailbird users tend to miss.
Your files: Imports contacts from .csv or .vcf and calendars from .ics. IMAP mail arrives from the server.
Does Mailbird run on Linux?
Verdict: No
No. Mailbird states on its own site that it is available for Windows and Mac, and there is no Linux version, so you will need another mail app after the switch.
Mailbird's site says plainly that the app is available for Windows and Mac and that a licence bought there covers both. Linux is not mentioned anywhere on the product pages, and no installer exists.
Moving is less painful than it looks, because Mailbird does not really own your mail. It connects to Gmail, Outlook.com or your provider over IMAP, which means the messages sit on the mail server. Put the same account into a Linux mail app and your inbox and folders come straight back.
What does not come back automatically is the local material. Export your contacts to a .csv or .vcf file, and if you used Mailbird's calendar, export it to .ics. Both formats import into Thunderbird and Evolution. Do this before you wipe Windows, because Mailbird stores its data in its own database that Linux apps cannot read.
Worth noting if you paid for a lifetime licence. It does not transfer to anything on Linux, and the free replacements below cost nothing, so there is no second payment to plan for.
What to use instead of Mailbird
Evolution
Close matchFreeMail, calendar, contacts and tasks together, and the better choice for a work Microsoft 365 or Exchange account.
Your files: Imports .vcf contacts and .ics calendars.
Geary
Different way of workingFreeA plainer, lighter inbox. Good if Mailbird was mainly about a tidy screen rather than the extra apps bolted on the side.
Your files: Mail only, fetched from the server.
This doesn't have to stop you
One stubborn program doesn't have to decide the whole question. You can keep Windows on the same PC and restart into it only when you need Mailbird. Everything else you do can move.
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