Troubleshooting Guide: Fix dyld Library Not Loaded Error for libicui18n.62.dylib

When working with macOS applications, you might encounter an error related to the libicui18n.62.dylib library. This library is a part of the International Components for Unicode (ICU) library, which is widely used for internationalization and Unicode support.

The error might look like this:

dyld: Library not loaded: /usr/local/opt/icu4c/lib/libicui18n.62.dylib
  Referenced from: /path/to/your/app
  Reason: image not found

To help you resolve this error, this guide provides step-by-step instructions for fixing the dyld Library not loaded error for libicui18n.62.dylib on macOS.


Before proceeding, ensure that you have the following installed on your system:

  1. Homebrew - A package manager for macOS.
  2. Xcode Command Line Tools - Required for building certain libraries.

Step 1: Install ICU4C Library

First, you need to install the ICU4C library using Homebrew. To do so, open the Terminal and run the following command:

brew install icu4c

This command installs the ICU4C library, which includes libicui18n.62.dylib.

Step 2: Update Your Environment Variables

Next, you need to update your environment variables to include the path to the ICU4C library. Add the following lines to your ~/.bash_profile or ~/.zshrc file, depending on your shell:

export LDFLAGS="-L/usr/local/opt/icu4c/lib"
export CPPFLAGS="-I/usr/local/opt/icu4c/include"

After saving the changes, run the following command to apply the updated environment variables:

source ~/.bash_profile
# Or
source ~/.zshrc

Step 3: Rebuild Your Application

Now, rebuild your application to ensure it links against the correct version of the ICU4C library. Following the rebuild, the dyld Library not loaded error for libicui18n.62.dylib should be resolved.


1. Why is the ICU4C library required?

The ICU4C library provides support for Unicode and internationalization, which is essential for many macOS applications. Some applications, such as those using the Boost.Locale library, depend on ICU4C for proper functioning.

2. Can I use another version of the ICU4C library?

Yes, you can use a different version of the ICU4C library, but you must ensure that your application is compatible with that version. To install a specific version, use the following command:

brew install icu4c@<version>

3. How can I check if the ICU4C library is installed correctly?

To verify the installation, run the following command:

brew info icu4c

This command displays information about the installed ICU4C library, including the version and the paths to the library files.

4. What should I do if I still encounter the dyld Library not loaded error?

If you still face the error, ensure that you have followed all the steps in this guide, especially the steps related to updating environment variables and rebuilding your application. If the issue persists, consider seeking help on Stack Overflow or the ICU mailing list.

5. Are there any alternatives to ICU4C?

Yes, there are alternative libraries available for Unicode and internationalization support, such as UTF8-CPP and libunistring. However, these libraries might not provide the same level of functionality as ICU4C.

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