dual boot - Install Ubuntu 18.04 alongside two Windows 10

My computer setup is:

• 1- SSD 120GB


• 1- HDD 320GB


• 1- HDD 1TB

I have two partitions on SSD of Windows 10 (one for work, another for games/testing/whatever) and I want to install Ubuntu on my 320GB HDD.
However, Ubuntu installer doesn't recognize Windows.

I tried to select "More options" to make the partitions on my own but when installer start said "errno 5 input/output"
I redownloaded ISO, tried other pendrives and every USB connection of my PC but always the same error.

Is there anything I can do?

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EDIT:

I managed to install Ubuntu on my 320GB hard drive but now GRUB is not detecting Windows10 partitions.

I tried to use Boot-repair but despite "successfully boot repaired", only Ubuntu appears in GRUB.

Here is a pastebin of Boot-repair log: http://paste.ubuntu.com/p/5KbYMRxqg9/

• /sda (windows system partitions)
  
  
  
  
  • /sda1 Windows 10 Work partition
  
  
  • /sda2 Windows 10 Fun partition
  
  
  • /sda3 Windows Reserved Partition
  
  


• /sdb (Storage)


• /sdc (Ubuntu)
  
  
  
  
  
  • /sdc1 Ubuntu 18.04
  
  
  • /sdc2 /Boot (partition recommended by Boot-repair)
  
  

Any ideas?