3.9.2
System:
OS: Windows 10
CPU: (12) x64 Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz
Binaries:
Node: 10.16.0 - C:\Program Files\nodejs\node.EXE
Yarn: 1.9.4 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
npm: 6.10.1 - C:\Program Files\nodejs\npm.CMD
Browsers:
Edge: 42.17134.1.0
npmGlobalPackages:
@vue/cli: Not Found
vue create sample-appA new project is created.
The following error is thrown Error: Failed to load plugin prettier: Cannot find module 'eslint-plugin-prettier'
The same occurs on old project when deleting yarn.lock/package-lock.json and reinstalling dependencies.
Installing manually "eslint-plugin-prettier" fixes the error, but I believe that this should be a dependency of "@vue/eslint-config-prettier" maybe...
Same here.

Same issue.
yarn install eslint-plugin-prettier solved the problem.
@gabemule You are probably correct.
Most helpful comment
The same occurs on old project when deleting yarn.lock/package-lock.json and reinstalling dependencies.
Installing manually "eslint-plugin-prettier" fixes the error, but I believe that this should be a dependency of "@vue/eslint-config-prettier" maybe...