We are aware of an issue whereby ALAC files in your Serato DJ Pro & Lite library will show as corrupt, and will not be playable, on Windows 7, 8, and 8.1.

We are currently investigating this, but as a work-around, we suggest the following steps:

• Re-encode your files to another lossless format. AIFF or WAV can be re-encoded to, using iTunes, here or by using other third-party software like Audacity.
  NOTE: You will need to re-analyse, and re-add Cue points, Loops, Flips, and other metadata added by Serato DJ to the newly re-encoded file.
• Update your OS to Windows 10. This might be a better option if you have a lot of ALAC files in your library.
• Use the 32-bit version of Serato DJ Pro/Lite. Please get in touch with our Support team if you want this, here.