EFI : Its required for the UEFI BIOS to recognize that drive is bootable Microsoft reserved : Reserved by windows for it's own dirty tasks   WINRETOOLS : It has windows recovery tools , RESET/REFRESH/Advanced boot options Image : Dell's OEM image, without this you wont be able to factory RESET machine. You can still use windows RESET though DELLSUPPORT : This is for SupportAssist OS recovery which is Dell's own recovery environment can be access from F12 menu   Yes you should do a clean Format on HDD for Installing Linux at any point of time you wanna come back to Windows you can download a copy on a USB from Microsoft or Dell  
The Dell laptop came with Windows 10 installed and the following partitions: I want to remove Windows and install Linux. Should I keep the DELLSUPPORT partition?  I have not been able to find a clear explanation of what is does or how it is used. Is it used only by Windows, or is it used by the BIOS? If I delete it, what functionality do I lose? Thanks    
Partitions on Dell laptop