How to verify a copy is identical before you delete the original

Q: Can I check a copy RoomDisk didn’t make?

Yes. Use Backed up? on the phone: pick any files and it tells you which are already on the disk, by what’s inside them.

A file that “looks fine” can still be damaged. RoomDisk checks the exact contents of every file on both devices, so a single wrong byte is caught.

What RoomDisk does

The sending device checks each file’s exact contents.
The disk writes the file, reads it back and checks it again.
Only files whose checks match are counted as safe to delete.
Each batch writes a receipt on the disk, listing every file that was checked.

Check files any time

On the phone, Backed up? checks any files against the disk by what’s inside them, not by their names.

Why “it opened fine” isn’t enough

Copies can go wrong without any warning: a cable or drive that drops out mid-write, a flash drive with failing memory, or an app that renames or skips files. A damaged photo may still open, with a grey band or missing half. Checking the contents on both sides is the only quick way to know every byte matches.

Check the whole disk later

Drives and old phones can develop errors over time. In the disk’s Settings, Check the disk re-reads every file and makes sure it’s exactly as it arrived, so you find a problem while the original still exists.

Questions

How does the check work?

RoomDisk works out a short code from everything inside a file. Change a single byte and the code changes completely, so matching codes on both devices mean identical files.

Can I check a copy RoomDisk didn’t make?

Yes. Use Backed up? on the phone: pick any files and it tells you which are already on the disk, by what’s inside them.

Does checking slow the transfer down?

Slightly. The check happens while the file is being sent, so most of the work overlaps.

Try it with the two devices you have

Pay once, keep it. Nothing to install, no account.

Open RoomDisk