Toast 12 Titanium .. How do I burn a *lossless* data blu-ray disc?


macrumors regular
Original poster
Jul 11, 2014
Hello. I need some help with Toast 12 Titanium .. How do I burn a *lossless* data blu-ray disc?

I've gone through all the preferences possible, emptied my "Trash", repaired disk permissions, restarted my computer.. everything.. but when I add a folder to the window, it calculates the folder as being a few gigabytes smaller than the original.. I don't see an option anywhere that is allowing me to select render-quality or to avoid using "compression".. Even in the "Options" tab (right next to the "Media" tab) there is no option for compression/no compression..

I've also tried compressing my original data into .zip folder and then adding it to Toast, which still ended up importing a filesize smaller than that of the original..

I am looking to back up very valuable information and need to make sure that every single file is exactly as they were originally (aka no compression whatsoever)..

Can anybody help me in how I can go about making an *exact/flawless/no compression* blu-ray data disk in Toast 12 Titanium?

Thank you so much!

Dave Braine

macrumors 68040
Mar 19, 2008
Warrington, UK
First of all, you will need an external BluRay burner, as you can't do this using your Mac's burner.

Can't help with the "lossless" bit though.


macrumors 68040
Oct 25, 2004
There are different ways of measuring the size of files.

Sometimes 1,000,000,000 bytes is 1 GB.
Sometimes 1,073,741,824 bytes is 1 GB (1024 * 1024 * 1024).

Likewise for MB

You may be running into a case where the sizes are being measured differently.

Also, on hard drives, files are stored into blocks, where each block consists of a certain number of bytes. e.g., 1024 bytes. A file will use an entire block, even it if needs only one byte. Sometimes file sizes are reported in terms of how many bytes the blocks allocated to the file take up (That's useful when you want to know how much disk space the file consumes). However, files burned on an optical disc are not arranged into blocks like this. So that, too, might explain the discrepancy.

To check the backup: (1) create the backup; (2) restore the backup to the same drive as the original but in a different place; (3) compare the restored copy to the original.

If you see that they are identical, you're in good shape. (It's a good idea to validate your backup process like this, even if you aren't worried about file sizes... often people don't try out their backup until the day they actually need it... obviously at that point it's too late to fix any issues.)
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