diff --git a/README.md b/README.md
index c59e0778812..074f0fc4901 100644
--- a/README.md
+++ b/README.md
@@ -117,7 +117,6 @@ require'nvim-tree'.setup {
 require'nvim-tree'.setup { -- BEGIN_DEFAULT_OPTS
   auto_reload_on_write = true,
   disable_netrw = false,
-  hide_root_folder = false,
   hijack_cursor = false,
   hijack_netrw = true,
   hijack_unnamed_buffer_when_opening = false,
@@ -130,6 +129,7 @@ require'nvim-tree'.setup { -- BEGIN_DEFAULT_OPTS
   view = {
     width = 30,
     height = 30,
+    hide_root_folder = false,
     side = "left",
     preserve_window_proportions = false,
     number = false,
@@ -166,7 +166,7 @@ require'nvim-tree'.setup { -- BEGIN_DEFAULT_OPTS
   },
   ignore_ft_on_setup = {},
   system_open = {
-    cmd = nil,
+    cmd = "",
     args = {},
   },
   diagnostics = {
diff --git a/doc/nvim-tree-lua.txt b/doc/nvim-tree-lua.txt
index b2019508f86..face92e68a0 100644
--- a/doc/nvim-tree-lua.txt
+++ b/doc/nvim-tree-lua.txt
@@ -82,11 +82,11 @@ SETUP                                *nvim-tree.setup*
 To configure the tree (and make it runnable), you should call the setup
 function.
 
+Values may be functions. Warning: this may result in unexpected behaviour.
 >
     require("nvim-tree").setup { -- BEGIN_DEFAULT_OPTS
       auto_reload_on_write = true,
       disable_netrw = false,
-      hide_root_folder = false,
       hijack_cursor = false,
       hijack_netrw = true,
       hijack_unnamed_buffer_when_opening = false,
@@ -99,6 +99,7 @@ function.
       view = {
         width = 30,
         height = 30,
+        hide_root_folder = false,
         side = "left",
         preserve_window_proportions = false,
         number = false,
@@ -135,7 +136,7 @@ function.
       },
       ignore_ft_on_setup = {},
       system_open = {
-        cmd = nil,
+        cmd = "",
         args = {},
       },
       diagnostics = {
@@ -311,10 +312,10 @@ Here is a list of the options available in the setup call:
 *nvim-tree.system_open*
 - |system_open|: configuration options for the system open command
 
-  - |system_open.cmd|: the command to run, leaving nil should work but
+  - |system_open.cmd|: the command to run, leaving empty should work but
     useful if you want to override the default command with another one.
     type: `string`
-    default: `nil`
+    default: `""`
 
   - |system_open.args|: the command arguments as a list
     type: `{string}`
diff --git a/lua/nvim-tree.lua b/lua/nvim-tree.lua
index 651bbf620be..0a56efc7e1d 100644
--- a/lua/nvim-tree.lua
+++ b/lua/nvim-tree.lua
@@ -311,7 +311,6 @@ end
 local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
   auto_reload_on_write = true,
   disable_netrw = false,
-  hide_root_folder = false,
   hijack_cursor = false,
   hijack_netrw = true,
   hijack_unnamed_buffer_when_opening = false,
@@ -324,6 +323,7 @@ local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
   view = {
     width = 30,
     height = 30,
+    hide_root_folder = false,
     side = "left",
     preserve_window_proportions = false,
     number = false,
@@ -360,7 +360,7 @@ local DEFAULT_OPTS = { -- BEGIN_DEFAULT_OPTS
   },
   ignore_ft_on_setup = {},
   system_open = {
-    cmd = nil,
+    cmd = "",
     args = {},
   },
   diagnostics = {
@@ -429,16 +429,53 @@ local function merge_options(conf)
   return vim.tbl_deep_extend("force", DEFAULT_OPTS, conf or {})
 end
 
+local function validate_options(conf)
+  local msg
+
+  local function validate(user, def, prefix)
+    -- only compare tables with contents that are not integer indexed
+    if type(user) ~= "table" or type(def) ~= "table" or not next(def) or type(next(def)) == "number" then
+      return
+    end
+
+    for k, v in pairs(user) do
+      local invalid
+      if def[k] == nil then
+        -- option does not exist
+        invalid = string.format("unknown option: %s%s", prefix, k)
+      elseif type(v) ~= type(def[k]) and type(v) ~= "function" then
+        -- option is of the wrong type and is not a function
+        invalid = string.format("invalid option: %s%s expected: %s actual: %s", prefix, k, type(def[k]), type(v))
+      end
+
+      if invalid then
+        if msg then
+          msg = string.format("%s | %s", msg, invalid)
+        else
+          msg = string.format("%s", invalid)
+        end
+        user[k] = nil
+      else
+        validate(v, def[k], prefix .. k .. ".")
+      end
+    end
+  end
+
+  validate(conf, DEFAULT_OPTS, "")
+
+  if msg then
+    utils.warn(msg)
+  end
+end
+
 function M.setup(conf)
   legacy.migrate_legacy_options(conf or {})
 
+  validate_options(conf)
+
   local opts = merge_options(conf)
   local netrw_disabled = opts.disable_netrw or opts.hijack_netrw
 
-  if opts.auto_close then
-    utils.warn "auto close feature has been removed, see note in the README (tips & reminder section)"
-  end
-
   _config.update_focused_file = opts.update_focused_file
   _config.open_on_setup = opts.open_on_setup
   _config.open_on_setup_file = opts.open_on_setup_file
diff --git a/lua/nvim-tree/actions/system-open.lua b/lua/nvim-tree/actions/system-open.lua
index b0f63596429..e44e357a72c 100644
--- a/lua/nvim-tree/actions/system-open.lua
+++ b/lua/nvim-tree/actions/system-open.lua
@@ -9,7 +9,7 @@ local M = {
 }
 
 function M.fn(node)
-  if not M.config.system_open.cmd then
+  if #M.config.system_open.cmd == 0 then
     require("nvim-tree.utils").warn "Cannot open file with system application. Unrecognized platform."
     return
   end
@@ -53,7 +53,7 @@ end
 function M.setup(opts)
   M.config.system_open = opts or {}
 
-  if not M.config.system_open.cmd then
+  if #M.config.system_open.cmd == 0 then
     if M.config.is_windows then
       M.config.system_open = {
         cmd = "cmd",
diff --git a/lua/nvim-tree/legacy.lua b/lua/nvim-tree/legacy.lua
index f4023c628d7..3030630a933 100644
--- a/lua/nvim-tree/legacy.lua
+++ b/lua/nvim-tree/legacy.lua
@@ -5,7 +5,7 @@ local M = {}
 -- TODO update git.io/JPhyt when adding a migration
 
 -- migrate the g: to o if the user has not specified that when calling setup
-local migrations = {
+local g_migrations = {
   nvim_tree_disable_netrw = function(o)
     if o.disable_netrw == nil then
       o.disable_netrw = vim.g.nvim_tree_disable_netrw ~= 0
@@ -178,22 +178,7 @@ local migrations = {
   end,
 }
 
-function M.migrate_legacy_options(opts)
-  local msg = nil
-
-  -- g: options
-  for g, m in pairs(migrations) do
-    if vim.fn.exists("g:" .. g) ~= 0 then
-      m(opts)
-      msg = (msg and msg .. ", " or "Following options were moved to setup, see git.io/JPhyt: ") .. g
-    end
-  end
-
-  if msg then
-    require("nvim-tree.utils").warn(msg)
-  end
-
-  -- regular opts
+local function refactored(opts)
   if opts.view then
     if opts.view.mappings then
       if opts.view.mappings.list then
@@ -207,4 +192,31 @@ function M.migrate_legacy_options(opts)
   end
 end
 
+local function removed(opts)
+  if opts.auto_close then
+    utils.warn "auto close feature has been removed, see note in the README (tips & reminder section)"
+    opts.auto_close = nil
+  end
+end
+
+function M.migrate_legacy_options(opts)
+  -- g: options
+  local msg
+  for g, m in pairs(g_migrations) do
+    if vim.fn.exists("g:" .. g) ~= 0 then
+      m(opts)
+      msg = (msg and msg .. ", " or "Following options were moved to setup, see git.io/JPhyt: ") .. g
+    end
+  end
+  if msg then
+    utils.warn(msg)
+  end
+
+  -- silently move
+  refactored(opts)
+
+  -- warn and delete
+  removed(opts)
+end
+
 return M