How to make BackBlaze faster?

I was struggling a lot to make uploads of BackBlaze complete faster. An have discovered an issue under Windows 10 (might be relevant on earlier versions as well) while the system is was heavy load: a process called MsMpEng.exe was using of a lot of disk and CPU: Windows Defender checking everything mindlessly.
I had added exclusions even for itself, and this made the system a lot more responsive and performant!

Process exclusions

I tried to add only processes which only read files, big files, or lots of them, but are not used to put new files onto the system (as opposed to e.g. totalcmd.exe)
I added these exclusions:

• 7zG.exe
• bztransmit64.exe
• bztrans64_thread00.exe
• bztrans64_thread01.exe
• bztrans64_thread02.exe
• bztrans64_thread03.exe
• bztrans64_thread04.exe
• bztrans64_thread05.exe
• bztrans64_thread06.exe
• bztrans64_thread07.exe
• bztrans64_thread08.exe
• bztrans64_thread09.exe
• dwm.exe
• msmpeng.exe
• perfmon.exe
• searchfilterhost.exe
• searchindexer.exe
• searchprotocolhost.exe

File type exclusions

Mostly large, non-executable media files:

• avi
• jpeg
• jpg
• mkv
• mp3
• mp4
• mpeg
• mpg
• orf
• ts

Location exclusions

• C:\Program  Files\Windows Defender
• ... 

Change Drive Letter and Paths greyed out? (Windows 7)

If you use Backblaze cloud backup it can be utterly frustrating that disconnecting and reconnecting USB drives can change their drive letters, and Backblaze has no method of cleverly "following"them.

Even more frustrating, that they do not provide a knowledge base article how to fix it (change it back).

But the worst thing happens, when for some reason you cannot do it right clicking your computer, then "Manage" then "Disk Management", then right clicking the Volume (not the disk!) with the improper drive letter: for one out of my three USB HDDs that option is greyed out!

Let's cut to the chase: i found the solution on this forum:
1. Open a command prompt.
2. Type in diskpart.
3. Type list disk to see a list of disks.
4. Type select disk #  (where # is the disk you want).
5. Type list volume to see partitions.
6. Type select volume #  (where # is the volume you want).
7. Type assign letter=x  (where x is the drive letter).

Using a command line and diskpart just worked for me! YMMW!