diff --git a/changelog.d/downloader/3153.bugfix.rst b/changelog.d/downloader/3153.bugfix.rst
new file mode 100644
index 000000000..fd8d74945
--- /dev/null
+++ b/changelog.d/downloader/3153.bugfix.rst
@@ -0,0 +1 @@
+Fixed an error on repo add from empty string values for the `install_msg` info.json field.
diff --git a/redbot/cogs/downloader/downloader.py b/redbot/cogs/downloader/downloader.py
index b12ac7ae2..094f33f3e 100644
--- a/redbot/cogs/downloader/downloader.py
+++ b/redbot/cogs/downloader/downloader.py
@@ -462,7 +462,7 @@ class Downloader(commands.Cog):
             )
         else:
             await ctx.send(_("Repo `{name}` successfully added.").format(name=name))
-            if repo.install_msg is not None:
+            if repo.install_msg:
                 await ctx.send(repo.install_msg.replace("[p]", ctx.prefix))
 
     @repo.command(name="delete", aliases=["remove", "del"], usage="<repo_name>")