try :
- Downgrade to v1.2.0.399 w/ or w/o Deleted the folder (backup first if need)
- reinstall latest version
- try to run program
for the further. if u use ext hdd usb for firmware source
first, connect ur hdd at the same port or drive label, mean like E:\ F:\ or ...
than u can open the tool w/o worry about Andriod ToolBox can't open
u can Download old version from here
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Thank you and good luck