Older Version of Audacity files huge

Hi, I have recorded an entire audiobook on the older version of audacity (I can’t remember which version it was, but I began recording in 2020) The program became very slow and then crashed before I realized that there was a new version. I installed the new version Audacity 3.1.3 but when I opened my files to edit them, they imported in as HUGE! 19KB went to 30 000KB. I have some files which have been imported as just short of a gig. I have no idea what to do. Have I lost everything? Please, can anyone advise? Many thanks

Before Audacity 3.0, Audacity projects had two parts. There was an “AUP” file, and a “_data” folder. The “_data” folder contained the audio data, and the “AUP” file contained the instructions that told Audacity how to put the data together to create the project. The “AUP” file did not contain any audio data, so it was relatively tiny. Audio data requires a lot of disk space, but the audio data was all in the separate “_data” folder.

Audacity 3.0 introduced a new file format - “AUP3”. An “AUP3” file contains an entire Audacity project, including all of the audio data. An AUP3 project is typically about the same size as an old “AUP file” + “_data folder”.

As Audacity is designed for high quality audio work, the audio data is stored in a very high quality format; “32-bit float PCM”. This supports better than CD quality, and requires about double the disk space of CD audio data. CD audio uses around 10 MB per minute of stereo audio. Assuming the same sample rate as a CD (44100 samples per second), 32-bit float uses around 20 MB per minute of stereo audio.

Thank you…I’m still a bit lost though. Are my files salvageable? Thanks

No idea. You didn’t tell us if the project is playable after importing into Audacity 3.1.3. If it plays correctly, then you have recovered it.