Julia 1.6.6 LTS / 1.7.3 / 1.8.0-rc1 | Pkg.update() → "could not download registries (thread failed to start)"

Hello,

julia> versioninfo()
Julia Version 1.7.3
Commit 742b9abb4d (2022-05-06 12:58 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-12.0.1 (ORCJIT, skylake)

This issue started after I upgraded from Julia 1.7.2 to 1.7.3 as documented in detail at Issues on GitHub

Upgrading from 1.7.3 to 1.8.0-rc1 did not solve the issue.
Downgrading from 1.8.0-rc1 to 1.6.6 LTS did not do so either.

Aside from uninstalling the Julia version, I tried deleting the

C:\Users\Audrius-St\.julia

directory. This was a mistake as I am now unable to add the packages that I require.

For example,

Pkg.add("GLMakie")
  Installing known registries into `C:\Users\Audrius-St\.julia`
┌ Warning: could not download https://pkg.julialang.org/registries
. . .

So I am now dead in the water with regards to being able to use any recent Julia release.

Has anyone else encountered this issue?
If so, then I would appreciate learning how to fix the problem.

Is there any chance that you’re behind some sort of aggressive firewall that could be blocking Julia’s access to https://pkg.julialang.org/registries ?

Yes, thank you. Missing the forest for the trees.
As I’ve never encountered any firewall access/download blocking issues before with the security software I use, it did not occur to me. Once I updated to the most recent version of the security software the issue was resolved.