Unity 6 Asset Import "Copying Files" Extremely Slow

Since upgrading to Unity 6, asset import is taking a lifetime during the “Copying files…” phase. For example, Dialogue System for Unity takes upwards of 15+ minutes for what should be a quick 5 minute process or less.

This is happening on a 4TB PCIe 4.0 NVMe SSD. So speed is not an issue. And the package size is only 32.4 MB so buffer overload on the SSD shouldn’t be a concern either.

Not sure what’s the reason, but it’s happening to all assets except for Shaders; they seem to import on a somewhat regular time schedule, if slightly longer than under the prior LTS.

Joan,

Thank you for the feedback. I am using 6000.0.32f1. Anti-virus was already disabled for them, but I made additions. The compression is disabled. The issue is still recurring.

What should I be looking for in the logs?

How many files are being imported, do you have a rough idea? And this “copying files” does this occur when importing the asset via Package Manager or .unitypackage? Or is this happening every time you work with that asset?

Does it take the same time when you create a new, empty project and import the asset there?

In some cases, such an issue may be caused by unoptimized editor scripts. Be it unnecessary, repeated imports and saves, or simply not using Start/StopBatchEditing when looping over files to be imported. And even editor scripts that hook into asset import or domain reload callbacks can severely degrade editor performance.

Try opening the Profiler, set it in deep profiling mode and editor profiling, then run the import and check the profiler output and callstack to get an idea where the most time is being spent.

PS: I flagged the first response as Spam since it is clearly AI fabricated.

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Same for me. When comparing the same project in Unity 2022.3 and Unity 6, the time required to import any asset is roughly triplicated.

To be honest, this is one of the reasons why I have not migrated to Unity 6 yet.