diff --git a/locales/en.json b/locales/en.json
index 044f145e5..d6784a78d 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -220,6 +220,7 @@
     "diagnosis_http_bad_status_code": "Could not reach your server as expected, it returned a bad status code. It might be that another machine answered instead of your server. You should check that you're correctly forwarding port 80, that your nginx configuration is up to date, and that a reverse-proxy is not interfering.",
     "diagnosis_http_unreachable": "Domain {domain} is unreachable through HTTP from outside.",
     "diagnosis_unknown_categories": "The following categories are unknown: {categories}",
+    "diagnosis_never_ran_yet": "It looks like this server was setup recently and there's no diagnosis report to show yet. You should start by running a full diagnosis, either from the webadmin or using 'yunohost diagnosis run' from the command line.",
     "domain_cannot_remove_main": "You cannot remove '{domain:s}' since it's the main domain, you first need to set another domain as the main domain using 'yunohost domain main-domain -n <another-domain>'; here is the list of candidate domains: {other_domains:s}",
     "domain_cannot_remove_main_add_new_one": "You cannot remove '{domain:s}' since it's the main domain and your only domain, you need to first add another domain using 'yunohost domain add <another-domain.com>', then set is as the main domain using 'yunohost domain main-domain -n <another-domain.com>' and then you can remove the domain '{domain:s}' using 'yunohost domain remove {domain:s}'.'",
     "domain_cert_gen_failed": "Could not generate certificate",
diff --git a/src/yunohost/diagnosis.py b/src/yunohost/diagnosis.py
index 018140a49..db791fcdf 100644
--- a/src/yunohost/diagnosis.py
+++ b/src/yunohost/diagnosis.py
@@ -58,6 +58,10 @@ def diagnosis_show(categories=[], issues=False, full=False, share=False):
         if unknown_categories:
             raise YunohostError('diagnosis_unknown_categories', categories=", ".join(categories))
 
+    if not os.path.exists(DIAGNOSIS_CACHE):
+        logger.warning(m18n.n("diagnosis_never_ran_yet"))
+        return
+
     # Fetch all reports
     all_reports = []
     for category in categories: