Below are some of the issues I've ran into using the 4.0 & 4.0.1 update.

Issues
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1. Search lag is terrible. Please bring back instant results while typing.

2. My library columns were scrambled after updating from 3.3.5 to 4.0.

3. There’s a transparent horizontal scroll bar at the bottom of the library that sits over the last track, so you have to carefully click just above it to select the final song.

4. On my FLX10, the sampler no longer routes through the sampler knob. I’m forced to use one of the mixer channels instead. Reverting to 3.3.5 fixes this instantly.

5. Ctrl+Shift+Del now requires two presses to delete a track from the library and computer. I’ve only seen this happen on Windows, not macOS.

6. The new Files section is slower to navigate since single-clicking no longer expands folders. You now have to click directly on the arrow, just like crates.

7. The color column looks empty unless you assign a color. Previously, the dark grey default made the library feel more balanced.

8. The status column that used to be on the left is now split into two columns, which adds clutter and unnecessary blank space. It just looks off compared to previous versions.

9. After reverting to 3.3.5, the history from the sets I played in 4.0 and 4.0.1 no longer shows up. It seems like the update may have changed the history path or format.

Summary
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The addition of right-click context menus, crate colours, and being able to search crates is fantastic. These features completely changed the way I sort and manage my library. Unfortunately, the improvements were short lived because the issues far outweigh the benefits. Serato 4.x still needs a lot of work. I used it for a few gigs and really tried to overlook the obvious annoyances so I wouldn’t be biased toward the older versions, but the problems are too hard to ignore