diff --git a/nvm.sh b/nvm.sh
index 0d9efe6..e6a9f8d 100755
--- a/nvm.sh
+++ b/nvm.sh
@@ -1274,6 +1274,13 @@ nvm_die_on_prefix() {
     return 3
   fi
 
+  if [ -n "$NPM_CONFIG_PREFIX" ] && ! (nvm_tree_contains_path "$NVM_DIR" "$NPM_CONFIG_PREFIX" >/dev/null 2>&1); then
+    nvm deactivate >/dev/null 2>&1
+    echo >&2 "nvm is not compatible with the \"NPM_CONFIG_PREFIX\" environment variable: currently set to \"$NPM_CONFIG_PREFIX\""
+    echo >&2 "Run \`unset NPM_CONFIG_PREFIX\` to unset it."
+    return 4
+  fi
+
   if ! nvm_has 'npm'; then
     return
   fi
@@ -1291,7 +1298,7 @@ nvm_die_on_prefix() {
       else
         echo >&2 "Run \`$NVM_COMMAND\` to unset it."
       fi
-      return 4
+      return 10
     fi
   fi
 }
diff --git a/test/fast/Unit tests/nvm_die_on_prefix b/test/fast/Unit tests/nvm_die_on_prefix
index 18e89a5..9a0260d 100755
--- a/test/fast/Unit tests/nvm_die_on_prefix	
+++ b/test/fast/Unit tests/nvm_die_on_prefix	
@@ -50,6 +50,13 @@ EXIT_CODE="$(PREFIX=bar nvm_die_on_prefix 0 foo >/dev/null 2>&1; echo $?)"
 [ "_$OUTPUT" = "_$EXPECTED_OUTPUT" ] || die "'PREFIX=bar nvm_die_on_prefix 0 foo' did not error with '$EXPECTED_OUTPUT'; got '$OUTPUT'"
 [ "_$EXIT_CODE" = "_3" ] || die "'PREFIX=bar nvm_die_on_prefix 0 foo' did not exit with 3; got '$EXIT_CODE'"
 
+OUTPUT="$(NPM_CONFIG_PREFIX=bar nvm_die_on_prefix 0 foo 2>&1)"
+EXPECTED_OUTPUT='nvm is not compatible with the "NPM_CONFIG_PREFIX" environment variable: currently set to "bar"
+Run `unset NPM_CONFIG_PREFIX` to unset it.'
+EXIT_CODE="$(NPM_CONFIG_PREFIX=bar nvm_die_on_prefix 0 foo >/dev/null 2>&1; echo $?)"
+[ "_$OUTPUT" = "_$EXPECTED_OUTPUT" ] || die "'NPM_CONFIG_PREFIX=bar nvm_die_on_prefix 0 foo' did not error with '$EXPECTED_OUTPUT'; got '$OUTPUT'"
+[ "_$EXIT_CODE" = "_4" ] || die "'NPM_CONFIG_PREFIX=bar nvm_die_on_prefix 0 foo' did not exit with 4; got '$EXIT_CODE'"
+
 npm() {
   local args
   args="$@"
@@ -62,6 +69,6 @@ EXPECTED_OUTPUT="nvm is not compatible with the npm config \"prefix\" option: cu
 Run \`npm config delete prefix\` or \`foo\` to unset it."
 EXIT_CODE="$(nvm_die_on_prefix 0 foo >/dev/null 2>&1; echo $?)"
 [ "_$OUTPUT" = "_$EXPECTED_OUTPUT" ] || die "'nvm_die_on_prefix 0 foo' did not error with '$EXPECTED_OUTPUT' with bad prefix set; got '$OUTPUT'"
-[ "_$EXIT_CODE" = "_4" ] || die "'nvm_die_on_prefix 0 foo' did not exit with 4 with bad prefix set; got '$EXIT_CODE'"
+[ "_$EXIT_CODE" = "_10" ] || die "'nvm_die_on_prefix 0 foo' did not exit with 10 with bad prefix set; got '$EXIT_CODE'"
 
 cleanup