diff --git a/src/universal/bin/sbt-launch-lib.bash b/src/universal/bin/sbt-launch-lib.bash
index 265e87431..b87cabae2 100755
--- a/src/universal/bin/sbt-launch-lib.bash
+++ b/src/universal/bin/sbt-launch-lib.bash
@@ -78,7 +78,7 @@ addDebugger () {
 }
 
 # a ham-fisted attempt to move some memory settings in concert
-# so they need not be dorked around with individually.
+# so they need not be messed around with individually.
 get_mem_opts () {
   local mem=${1:-1024}
   local perm=$(( $mem / 4 ))
@@ -86,7 +86,13 @@ get_mem_opts () {
   (( $perm < 1024 )) || perm=1024
   local codecache=$(( $perm / 2 ))
 
-  echo "-Xms${mem}m -Xmx${mem}m -XX:MaxPermSize=${perm}m -XX:ReservedCodeCacheSize=${codecache}m"
+  # if we detect any of these settings in ${java_opts} we need to NOT output our settings.
+  # The reason is the Xms/Xmx, if they don't line up, cause errors.
+  if [[ "${java_opts}" == *-Xmx* ]] || [[ "${java_opts}" == *-Xms* ]] || [[ "${java_opts}" == *-XX:MaxPermSize* ]] || [[ "${java_opts}" == *-XX:ReservedCodeCacheSize* ]]; then
+     echo ""
+  else 
+    echo "-Xms${mem}m -Xmx${mem}m -XX:MaxPermSize=${perm}m -XX:ReservedCodeCacheSize=${codecache}m"
+  fi
 }
 
 require_arg () {