Delete LL on machine with dual-boot

[gold_finger]

NOTE:  for any solution listed below, have a live LL USB/DVD handy where you will use GParted from it to delete the LL partition(s).

Answer depends on how the two OSs were installed (what boot mode both are using).


If both are installed in Legacy mode and LL's grub menu gives you the choice to boot into either OS on startup, then you'll need to have Windows 10's boot loader take back control of booting the computer before you delete LL, so computer boots properly without LL.


Unless you went through rather complicated procedure to get LL installed and working in UEFI mode (you would remember if you actually did this), I'm going to assume LL is installed in Legacy mode.  So main thing you need to determine is what boot mode is Windows using?


Answer will be Legacy mode if the following are true:

• You are able to boot into Windows from LL's grub menu choice on startup.
  
• In an LL terminal, if you run command sudo parted --list and see "msdos" listed next to "Partition Table" in the output.
  

If confirmed that Windows is in Legacy mode, do either of these things to have it take back control of booting the computer before you delete LL:

• Using original install disk or recovery disk for Windows, follow these instructions to repair MBR.
  
• Use Dual-boot Repair utility for Windows 10 (a GUI utility) to repair MBR without install/recovery disk.  (Don't personally know anything about this but found it referred to in this thread and OP there claims it worked.)
  

Once completed, computer should boot straight to Windows offering no choice for booting LL.


Now, reboot computer using live LL USB/DVD and open GParted from there.

• In GParted, right-click on the Swap partition and choose "swapoff".
  
• Delete your LL related partitions (should be any formatted as "ext4") and the Swap partition.
  
• Hit "Apply" button to carry out the deletions.
  
• Close GParted, shutdown computer when done.
  

Boot back into Windows when done and you can use its Disk Management utility to reclaim the space previously occupied by LL.




If Windows is installed in UEFI mode and LL in Legacy mode, then you probably have to invoke the appropriate boot mode during startup to boot into either of the two and LL's grub menu will either not show at all when you select booting in Legacy mode or it will show, but not give a choice for booting Windows.  Confirm for sure that Windows was installed in UEFI mode before deleting LL by doing either of these:

• Use terminal command sudo parted --list while booted in LL.  If "Partition Table" shows "gpt" then Windows is installed in UEFI mode.
  
• Follow instructions shown here while booted into Windows.
  

If confirmed that Windows is in UEFI mode, follow instructions above to delete LL's partitions while booted into live LL USB/DVD.  No need to fix Windows MBR first.  Just set UEFI/Bios to always boot in UEFI mode and Windows will boot every time.