diff --git a/dangerzone/container.py b/dangerzone/container.py
index 930de7a..cd7eb8d 100644
--- a/dangerzone/container.py
+++ b/dangerzone/container.py
@@ -52,11 +52,17 @@ def exec(args, stdout_callback=None):
 def exec_container(command, extra_args=[], stdout_callback=None):
     if container_tech == "podman":
         container_runtime = shutil.which("podman")
+        if container_runtime is None:
+            raise Exception(f"podman is not installed")
+
         platform_args = []
         security_args = ["--security-opt", "no-new-privileges"]
         security_args += ["--userns", "keep-id"]
     else:
         container_runtime = shutil.which("docker")
+        if container_runtime is None:
+            raise Exception(f"docker is not installed")
+
         platform_args = ["--platform", "linux/amd64"]
         security_args = ["--security-opt=no-new-privileges:true"]
 
diff --git a/dangerzone/global_common.py b/dangerzone/global_common.py
index 35f4da9..a979ff9 100644
--- a/dangerzone/global_common.py
+++ b/dangerzone/global_common.py
@@ -386,11 +386,15 @@ class GlobalCommon(object):
         )
         print(Back.BLACK + Fore.YELLOW + Style.DIM + "╰──────────────────────────╯")
 
-    def get_container_runtime(self):
+    def get_container_runtime(self) -> str:
         if platform.system() == "Linux":
-            return shutil.which("podman")
+            runtime_name = "podman"
         else:
-            return shutil.which("docker")
+            runtime_name = "docker"
+        runtime = shutil.which(runtime_name)
+        if runtime is None:
+            raise Exception(f"{runtime_name} is not installed")
+        return runtime
 
     def get_resource_path(self, filename: str) -> str:
         if getattr(sys, "dangerzone_dev", False):