This section provides information to help you troubleshoot and resolve or work around common issues that are related to the following tasks:
downloading and installing the SDK
creating, building, or deploying canisters
running the local canister execution environment
Migrating an existing project
Currently, there is no automatic migration or backward compatibility for any projects that you might have created using previous versions of the
dfx command-line interface. After upgrading to the latest version, you might see error or failure messages if you attempt to build or install a project created with a previous version of the
dfx command-line interface.
In many cases, however, you can continue to work with projects from a previous release by manually changing the dfx setting in the dfx.json configuration file, then rebuilding the project to be compatible with the version of the
dfx command-line interface you have currently installed.
For example, if you have a project that was created with
0.8.0, open the
dfx.json file in a text editor and change the
dfx setting to the latest version or remove the section entirely.
Restarting the local canister execution environment
In some cases, starting the local canister execution environment fails due to stale state. If you encounter issues when running
dfx start to start the local canister execution environment:
In the terminal that displays the IC emulation the execution environment uses, press Control-C to interrupt the local canister execution environment process.
Stop the local canister execution environment by running the following command:
Restart the local canister execution environment in a clean state by running the following command:
dfx start --clean
--cleanoption removes checkpoints and stale state information from your project’s cache so that you can restart the local canister execution environment and web server processes in a clean state.
Keep in mind, however, that if you reset the state information by running
dfx start --clean, your existing canisters are also removed.
dfx start --clean, recreate your canisters by running the following commands:
dfx canister create --all
dfx canister install --all
Removing the canisters directory
If you run into problems building or deploying canisters after successfully connecting to the IC and registering canister identifiers, you should remove the
canisters directory before attempting to rebuild or redeploy the canisters.
You can remove the
canisters directory for a project by running the following command in the project’s root directory:
rm -rf ./.dfx/* canisters/*
Many of the bugs you might encounter can be addressed by uninstalling and reinstalling the
dfx command-line interface. Here are a few ways to reinstall
If you only have one version of
dfx installed in your development environment, you can usually run the following command to uninstall and reinstall the latest version of
~/.cache/dfinity/uninstall.sh && sh -ci "$(curl -sSL https://smartcontracts.org/install.sh)"
If you have modified the location of the
dfx binary, you might want run the following command to uninstall the version of
dfx that is in your PATH, then reinstall the latest version of
rm -rf ~/.cache/dfinity && rm $(which dfx) && sh -ci "$(curl -sSL https://smartcontracts.org/install.sh)"
Some versions of the SDK prompted you to install Xcode when creating a new project on a macOS computer. The prompt has been removed and the
dfx new command does not require you to install any macOS developer tools. However, you should have Developer Command Line Tools installed if you want to create a Git repository for your project.
You can check whether you have the developer tools installed by running
xcode-select -p. You can install the developer tools by running
Failed build when using VMs
If you are running
dfx using a virtual machine image on Ubuntu or CentOS, you might see an error message that looks like this when you attempt to run the
dfx build command:
An error occurred:
message: "No such file or directory",
Address in use error or orphan processes
If you are developing projects locally, you often have the local canister execution environment running either in a separate terminal or in the background. If the local environment processes do not get properly terminated, you might see operating system errors indicating that an address is already in use or or be unable to stop processes normally using the
dfx stop command.
There are several scenarios in which you might encounter this issue. For example, if you run
dfx start in a local project directory then change to a different local project directory without first stopping the canister execution environment processes, you might see this issue.
If you encounter an issue where you suspect or you receive a message that an address is already in use or that a process is already running in the background, perform the following steps:
Run the following command to see which process is listening to the 8000 port if you are using the default binding to localhost:
lsof -i tcp:8000
Run the following command to terminate any orphan processes:
killall dfx replica
Close the current terminal and open a new terminal window.
In the new terminal, run the following command to run the local canister execution environment in a clean state:
dfx start --clean --background
Fixing memory leaks is an ongoing process. If you encounter any error messages related to memory leaks, you should do the following:
dfx stopto stop currently running processes.
dfxto prevent further degradation.
dfx startto restart replica processes.
Alternatively, you can remove the
.cache/dfinity directory and re-install the latest
dfx binary. For example:
rm -rf ~/.cache/dfinity && sh -ci "$(curl -sSL https://smartcontracts.org/install.sh)"