diff --git a/.github/workflows/mypy.yml b/.github/workflows/mypy.yml
index 7dd4347d53..08da614ce0 100644
--- a/.github/workflows/mypy.yml
+++ b/.github/workflows/mypy.yml
@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: mamba-org/setup-micromamba@v1
         with:
-          micromamba-version: "latest" # any version from https://github.com/mamba-org/micromamba-releases
+          micromamba-version: "1.5.10-0" # until https://github.com/mamba-org/setup-micromamba/issues/225 is resolved
           environment-file: environment.yml
           init-shell: bash
           cache-environment: true
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 674bc52c7b..fb11c8b556 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -135,7 +135,7 @@ jobs:
         uses: mamba-org/setup-micromamba@v1
         with:
           environment-name: pytensor-test
-          micromamba-version: "latest"
+          micromamba-version: "1.5.10-0" # until https://github.com/mamba-org/setup-micromamba/issues/225 is resolved
           init-shell: bash
           post-cleanup: "all"
           create-args: python=${{ matrix.python-version }}
@@ -209,7 +209,7 @@ jobs:
         uses: mamba-org/setup-micromamba@v1
         with:
           environment-name: pytensor-test
-          micromamba-version: "latest"
+          micromamba-version: "1.5.10-0" # until https://github.com/mamba-org/setup-micromamba/issues/225 is resolved
           init-shell: bash
           post-cleanup: "all"
       - name: Install dependencies