diff --git a/modules/uci-shell-install.lib b/modules/uci-shell-install.lib
index de8bebf..b4c795d 100644
--- a/modules/uci-shell-install.lib
+++ b/modules/uci-shell-install.lib
@@ -21,10 +21,10 @@
 
 # must! be run as sudo
 install_shell_base () {
-    if [[ $BASH_SHELL_BASE ]]; then
+    if [[ $BASH_SHELL_BASE ]] && [[ -d $BASH_SHELL_BASE ]]; then
       echo appears that UCI shell base is already installed at $BASH_SHELL_BASE 
       echo upgrade instead using: 'module_load uci-shell-install; update_shell_base'
-      return 1
+      [[ $1 == "-f" ]] && { shift; echo forcing reinstall; } || return 1
     fi
     if [[ ! $BASH_SHELL_GIT_URL ]]; then
       echo BASH_SHELL_GIT_URL must be set before install can proceed