Ubuntu终端执行flutter doctor命令失败，报curl握手错误

云上老周

2026-5-20

Fixing "curl: (35) gnutls_handshake() failed" Error When Running flutter doctor on Ubuntu

Hey there, I’ve dealt with this exact headache when setting up Flutter on Ubuntu—total roadblock, I know. Let’s walk through the most reliable fixes to get flutter doctor working again:

Update system packages and reinstall GnuTLS components
Outdated GnuTLS libraries are a common culprit here. Run these commands to refresh your system and fix any corrupted or old packages:
```
sudo apt update && sudo apt upgrade -y
sudo apt install --reinstall gnutls-bin libgnutls30
```
After this, try running flutter doctor again to see if the error clears up.
Switch curl to use OpenSSL instead of GnuTLS
Ubuntu’s default curl uses GnuTLS, which can sometimes have handshake issues with certain servers. Let’s swap it to OpenSSL:
1. Install the OpenSSL-backed curl package:
```
sudo apt install curl-openssl
```
2. Set it as the default curl version:
```
sudo update-alternatives --config curl
```
  When prompted, select the option for curl-openssl (it’ll have a path like /usr/bin/curl-openssl).
Disable proxy settings temporarily
If you’re using a system or environment proxy, it might be interfering with the TLS handshake. Try unsetting proxy variables first:
```
unset http_proxy https_proxy
```
If you have a GUI proxy enabled, head to Settings > Network > Proxy and toggle it off temporarily, then run flutter doctor again.
Manually install the Flutter SDK
If all else fails, skip the curl-based installation entirely:
1. Download the latest Flutter SDK zip from the official site (you can use your browser for this).
2. Extract it to a directory like ~/development/flutter (create the folder if it doesn’t exist).
3. Add Flutter’s bin directory to your PATH:
```
echo 'export PATH="$PATH:$HOME/development/flutter/bin"' >> ~/.bashrc
# If you use Zsh, replace .bashrc with .zshrc
```
4. Reload your shell configuration:
```
source ~/.bashrc
```
Now run flutter doctor—it should work without relying on curl for the setup.