electrum fails to start with "This application failed to start because it could not find or load the Qt platform plugin "xcb" in ""."

[sasoiliev]

Issue description

The electrum application fails to start with the message:

This application failed to start because it could not find or load the Qt platform plugin "xcb"
in "".

Reinstalling the application may fix this problem.
Aborted

Steps to reproduce

1. Install electrum: nix-env -iA nixos.electrum
2. Try to start it: electrum

Technical details

Please run nix-shell -p nix-info --run "nix-info -m" and paste the
results.

$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 4.15.7, NixOS, 17.09.3204.d16ffa15090 (Hummingbird)`
 - multi-user?: `yes`
 - sandbox: `no`
 - version: `nix-env (Nix) 1.11.16`
 - channels(root): `"nixos-17.09.3204.d16ffa15090"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs`

[Moredread]

Comments in PR #31470 might be relevant

[joachifm]

This is a general problem that affects all qt5 apps. I don't have a link at hand, but the qt maintainer has explained the problem in more detail (I hesitate to ping them to answer this yet again, however).

[joachifm]

See #24256 (comment)

[joachifm]

Also #33146