--- a/tools/profiler/core/platform.cpp
+++ b/tools/profiler/core/platform.cpp
@@ -2323,39 +2323,45 @@ profiler_init(void* aStackTop)
 
     const char* startupEntries = getenv("MOZ_PROFILER_STARTUP_ENTRIES");
     if (startupEntries && startupEntries[0] != '\0') {
       errno = 0;
       entries = strtol(startupEntries, nullptr, 10);
       if (errno == 0 && entries > 0) {
         LOG("- MOZ_PROFILER_STARTUP_ENTRIES = %d", entries);
       } else {
+        LOG("- MOZ_PROFILER_STARTUP_ENTRIES not a valid integer: %s",
+            startupEntries);
         PrintUsageThenExit(1);
       }
     }
 
     const char* startupInterval = getenv("MOZ_PROFILER_STARTUP_INTERVAL");
     if (startupInterval && startupInterval[0] != '\0') {
       errno = 0;
       interval = PR_strtod(startupInterval, nullptr);
       if (errno == 0 && interval > 0.0 && interval <= 1000.0) {
         LOG("- MOZ_PROFILER_STARTUP_INTERVAL = %f", interval);
       } else {
+        LOG("- MOZ_PROFILER_STARTUP_INTERVAL not a valid float: %s",
+            startupInterval);
         PrintUsageThenExit(1);
       }
     }
 
     const char* startupFeaturesBitfield =
       getenv("MOZ_PROFILER_STARTUP_FEATURES_BITFIELD");
     if (startupFeaturesBitfield && startupFeaturesBitfield[0] != '\0') {
       errno = 0;
       features = strtol(startupFeaturesBitfield, nullptr, 10);
       if (errno == 0 && features != 0) {
         LOG("- MOZ_PROFILER_STARTUP_FEATURES_BITFIELD = %d", features);
       } else {
+        LOG("- MOZ_PROFILER_STARTUP_FEATURES_BITFIELD not a valid integer: %s",
+            startupFeaturesBitfield);
         PrintUsageThenExit(1);
       }
     } else {
       const char* startupFeatures = getenv("MOZ_PROFILER_STARTUP_FEATURES");
       if (startupFeatures && startupFeatures[0] != '\0') {
         // Interpret startupFeatures as a list of feature strings, separated by
         // commas.
         UniquePtr<char[]> featureStringStorage;