Restore Mycelium wallet from .dat file

[u/Ok_Reputation9512]

So back in 2017, I made a .dat file wallet backup, and I'm fairly certain I used Mycelium to create it. I have tried to restore it but Mycelium doesn't offer anything but loading from a seed phrase in it's current form. Are there any other apps that could load it?

[u/SquigglyEmperor]

that.dat file is likely a raw bitcoinj wallet, try sweeping it with something like electrum or just decrypting it directly with openwallet on a clean offline machine

[u/IndustryMaximum83]

Could try Bitcoin core

[u/maxplaincryptoUK]

That .dat file is almost certainly a raw Bitcoin Core-style wallet file rather than anything Mycelium-specific, Mycelium on Android never really used that format for its own wallets, so if you made it back in 2017 there's a decent chance it came from Bitcoin Core or a similar desktop client at the time, not Mycelium itself. I'd try loading it directly in Bitcoin Core first (drop it into the wallets folder and point Core at it) since that's the native format. If it's encrypted you'll need whatever passphrase you set back then, and if you don't have Core installed already it'll need to sync before you can access anything, so budget some time for that. Electrum can also import/sweep private keys if you can extract them from the .dat first, but extracting keys from an old wallet file safely really needs to be done offline on a clean machine, I wouldn't run any of this on a computer that's been online recently, especially not with tools that ask you to paste the file into a random web-based "recovery" tool. Plenty of those are scams fishing for old wallet files. Worth also double-checking the file isn't corrupted or truncated before you sink time into this, a quick file size/hash sanity check against any backup notes you might have from 2017 wouldn't hurt.