Hi everyone, I'm new here! I try to resolve an issue : I just got a Tascam US-20x20. This is a second-hand unit. I've tried it on Pro Tools 12 and Reaper and I get the same problem : A lot of digital crackles! They appear only when I playback my recordings. The audio recorded is not altered by crackles, this is just a monitoring issue. The problem appears randomly. Sometimes it's ok, sometimes it's not. Here is a list of everything I tried to resolve this : - I disabled all Windows built-in audio devices in my system. - I changed buffer size to all available values - no luck! - I uninstalled/reinstalled Tascam drivers - My Tascam firmware is up to date. - I tried to change the USB 3.0 port where I plug my audio unit (there are 2 USB 3.0 and 1 USB 2.0 ports on my laptop). - I tried to plug the unit with a USB 2.0 cable on my USB 2.0 port. - I disabled wifi - I uninstalled/reinstalled USB 3.0 drivers in Windows - ASIO is selected in both Pro Tools and Reaper - I tried to power on the unit while the OS is up and running - I tried to power on the unit before powering on the computer - When I monitor CPU and RAM in Windows task manager, this is OK (CPU less than 20% and RAM less than 40%) - When I read audio and video files in Windows with the DAW closed, no problem, no crackles! Still crackles during the playback in the DAWs!!! My config : Lenovo Y50-70 i5 2.90 Ghz 8 GB RAM Windows 10 up to date Thanx so much for your help!