diff --git a/src/bin/julialauncher.rs b/src/bin/julialauncher.rs
index 1201237f..955e9e9a 100644
--- a/src/bin/julialauncher.rs
+++ b/src/bin/julialauncher.rs
@@ -163,9 +163,27 @@ fn get_julia_path_from_channel(
             .installed_channels
             .get(channel)
             .ok_or_else(|| match juliaup_channel_source {
-                JuliaupChannelSource::CmdLine => UserError { msg: format!("ERROR: Invalid Juliaup channel `{}` at command line.", channel).to_string() }.into(),
-                JuliaupChannelSource::EnvVar => UserError { msg: format!("ERROR: Invalid Juliaup channel `{}` in environment variable JULIAUP_CHANNEL.", channel).to_string() }.into(),
-                JuliaupChannelSource::Override => UserError { msg: format!("ERROR: Invalid Juliaup channel `{}` in directory override.", channel).to_string() }.into(),
+                JuliaupChannelSource::CmdLine => {
+                    if versions_db.available_channels.contains_key(channel) {
+                        UserError { msg: format!("`{}` is not installed. Please run `juliaup add {}` to install channel or version.", channel, channel) }
+                    } else {
+                        UserError { msg: format!("ERROR: Invalid Juliaup channel `{}`. Please run `juliaup list` to get a list of valid channels and versions.",  channel) }
+                    }
+                }.into(),
+                JuliaupChannelSource::EnvVar=> {
+                    if versions_db.available_channels.contains_key(channel) {
+                        UserError { msg: format!("`{}` for environment variable JULIAUP_CHANNEL is not installed. Please run `juliaup add {}` to install channel or version.", channel, channel) }
+                    } else {
+                        UserError { msg: format!("ERROR: Invalid Juliaup channel `{}` in environment variable JULIAUP_CHANNEL. Please run `juliaup list` to get a list of valid channels and versions.",  channel) }
+                    }
+                }.into(),
+                JuliaupChannelSource::Override=> {
+                    if versions_db.available_channels.contains_key(channel) {
+                        UserError { msg: format!("`{}` for directory override is not installed. Please run `juliaup add {}` to install channel or version.", channel, channel) }
+                    } else {
+                        UserError { msg: format!("ERROR: Invalid Juliaup channel `{}` in directory override. Please run `juliaup list` to get a list of valid channels and versions.",  channel) }
+                    }
+                }.into(),
                 JuliaupChannelSource::Default => anyhow!("The Juliaup configuration is in an inconsistent state, the currently configured default channel `{}` is not installed.", channel)
             })?;
 
diff --git a/tests/channel_selection.rs b/tests/channel_selection.rs
index 35034837..aabe1def 100644
--- a/tests/channel_selection.rs
+++ b/tests/channel_selection.rs
@@ -99,7 +99,7 @@ fn channel_selection() {
         .env("JULIAUP_DEPOT_PATH", depot_dir.path())
         .assert()
         .failure()
-        .stderr("ERROR: Invalid Juliaup channel `1.8.6` at command line.\n");
+        .stderr("ERROR: Invalid Juliaup channel `1.8.6`. Please run `juliaup list` to get a list of valid channels and versions.\n");
 
     Command::cargo_bin("julialauncher")
         .unwrap()
@@ -111,7 +111,7 @@ fn channel_selection() {
         .assert()
         .failure()
         .stderr(
-            "ERROR: Invalid Juliaup channel `1.7.4` in environment variable JULIAUP_CHANNEL.\n",
+            "ERROR: Invalid Juliaup channel `1.7.4` in environment variable JULIAUP_CHANNEL. Please run `juliaup list` to get a list of valid channels and versions.\n",
         );
 
     Command::cargo_bin("julialauncher")
@@ -124,5 +124,5 @@ fn channel_selection() {
         .env("JULIAUP_CHANNEL", "1.7.4")
         .assert()
         .failure()
-        .stderr("ERROR: Invalid Juliaup channel `1.8.6` at command line.\n");
+        .stderr("ERROR: Invalid Juliaup channel `1.8.6`. Please run `juliaup list` to get a list of valid channels and versions.\n");
 }