diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index dbb7a0cf..916b7f1a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -37,6 +37,8 @@ jobs:
       - uses: actions/checkout@v2
       - name: Install prerequisites
         run: >-
+          sudo apt-get update
+
           sudo apt-get install -y
           build-essential
           cmake
@@ -95,6 +97,8 @@ jobs:
           apt-get update
       - name: Install prerequisites
         run: >-
+          apt-get update
+
           apt-get install -y
           git
           cmake
@@ -145,6 +149,8 @@ jobs:
       - uses: actions/checkout@v2
       - name: Install prerequisites
         run: >-
+          brew update
+
           brew install
           cmake
           flex