NA: Transfer Thunderbird inbox from Windows 10 to Android

[FORANE]

I'm trying to transfer all 60,000 old emails from my Windows laptop Thunderbird inbox to my new Oneplus 13 running Android version 16.

Import doesn't work because the file is too big.
Ordinary downloading from server doesn't work because most emails no longer exist on the server.

I figured I would download them manually onto a flash drive. I was able to locate the relevant files on my laptop:
C:\Users\Admin\AppData\Roaming\Thunderbird\Profiles\miz0d5ei.default-esr\Mail\pop.gmail.com\inbox.msf and inbox.zip.msf. I was able to save them on the flash drive. I can find the relevant file on my android: Android/data/net.thunderbird.android/files Problem is android doesn't allow access to that file to read or write to it.

My phone is not rooted. Does anyone know a workaround?

 

[GeorgeC]

60,000 is a lot. I've got ~20 years of email in Thunderbird, one folder per year, where each folder only has a few thousand.

If I had to guess, you're running up against a stupid software trick somewhere in the stack, where something is gagging on too large a file, like a mbox >4G in size or something dumb like that.

tl;dr I'd split it up on the Thunderbird side before trying to move them.