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Hi Susana,

You cannot load partial customization files (CUIx) in AutoCAD for Mac as you can do in AC for Windows.
You have to do all customizations using CUI command:
https://help.autodesk.com/view/ACDMAC/2021/ENU/index.html?guid=GUID-7F8F4B26-EFAF-4033-B7B7-CA39FC4E...

https://help.autodesk.com/view/ACDMAC/2021/ENU/index.html?guid=GUID-0087582D-DCB5-440D-9EC4-BF6EB39F...

https://help.autodesk.com/view/ACDMAC/2021/ENU/index.html?guid=GUID-5EA33FF4-CF82-47BE-8F80-450DC1FD...

You can also customize Tool Sets palette on Mac:
https://help.autodesk.com/view/ACDMAC/2021/ENU/index.html?guid=GUID-80278E4A-D01B-43E6-BF9E-9DCFD18B...

https://www.youtube.com/watch?v=tA1FPYC-4Tk