Hey,
I’ve been running expo-cli 2.6.14 on a Windows 10 box without issue.
Attempted to upgrade to 2.11.1 by running npm install -g expo-cli.
Got what seems to be a file permissions error and now expo and expo-cli are gone and I’m not able to re-install. 
4205 timing action:finalize Completed in 205862ms
4206 verbose unlock done using C:\Users\bilstahp\AppData\Roaming\npm-cache\_locks\staging-46d923d1013940ca.lock for C:\Users\bilstahp\AppData\Roaming\npm\node_modules\.staging
4207 timing stage:rollbackFailedOptional Completed in 163ms
4208 timing stage:runTopLevelLifecycles Completed in 458966ms
4209 verbose stack Error: EPERM: operation not permitted, unlink 'C:\Users\bilstahp\AppData\Roaming\npm\node_modules\expo-cli\node_modules\.xdl.DELETE\binaries\windows\adb\AdbWinApi.dll'
4210 verbose cwd C:\Git\406-app
4211 verbose Windows_NT 10.0.16299
4212 verbose argv "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\bin\\npm-cli.js" "install" "-g" "expo-cli"
4213 verbose node v10.15.0
4214 verbose npm v6.4.1
4215 error path C:\Users\bilstahp\AppData\Roaming\npm\node_modules\expo-cli\node_modules\.xdl.DELETE\binaries\windows\adb\AdbWinApi.dll
4216 error code EPERM
4217 error errno -4048
4218 error syscall unlink
4219 error Error: EPERM: operation not permitted, unlink 'C:\Users\bilstahp\AppData\Roaming\npm\node_modules\expo-cli\node_modules\.xdl.DELETE\binaries\windows\adb\AdbWinApi.dll'
4219 error { [Error: EPERM: operation not permitted, unlink 'C:\Users\bilstahp\AppData\Roaming\npm\node_modules\expo-cli\node_modules\.xdl.DELETE\binaries\windows\adb\AdbWinApi.dll']
4219 error cause:
4219 error { Error: EPERM: operation not permitted, unlink 'C:\Users\bilstahp\AppData\Roaming\npm\node_modules\expo-cli\node_modules\.xdl.DELETE\binaries\windows\adb\AdbWinApi.dll'
4219 error errno: -4048,
4219 error code: 'EPERM',
4219 error syscall: 'unlink',
4219 error path:
4219 error 'C:\\Users\\bilstahp\\AppData\\Roaming\\npm\\node_modules\\expo-cli\\node_modules\\.xdl.DELETE\\binaries\\windows\\adb\\AdbWinApi.dll' },
4219 error stack:
4219 error 'Error: EPERM: operation not permitted, unlink \'C:\\Users\\bilstahp\\AppData\\Roaming\\npm\\node_modules\\expo-cli\\node_modules\\.xdl.DELETE\\binaries\\windows\\adb\\AdbWinApi.dll\'',
4219 error errno: -4048,
4219 error code: 'EPERM',
4219 error syscall: 'unlink',
4219 error path:
4219 error 'C:\\Users\\bilstahp\\AppData\\Roaming\\npm\\node_modules\\expo-cli\\node_modules\\.xdl.DELETE\\binaries\\windows\\adb\\AdbWinApi.dll',
4219 error parent: 'expo-cli' }
4220 error The operation was rejected by your operating system.
4220 error Its possible that the file was already in use (by a text editor or antivirus),
4220 error or that you lack permissions to access it.
4220 error
4220 error If you believe this might be a permissions issue, please double-check the
4220 error permissions of the file and its containing directories, or try running
4220 error the command again as root/Administrator (though this is not recommended).
4221 verbose exit [ -4048, true ]
I made sure WSL is enabled, and tried running PowerShell as Administrator and doing a npm install -g expo-cli… same result.
Any ideas?