diff --git a/rln/src/pm_tree_adapter.rs b/rln/src/pm_tree_adapter.rs
index 10cd433..40f13f8 100644
--- a/rln/src/pm_tree_adapter.rs
+++ b/rln/src/pm_tree_adapter.rs
@@ -58,9 +58,9 @@ impl FromStr for PmtreeConfig {
     fn from_str(s: &str) -> Result<Self> {
         let config: Value = serde_json::from_str(s)?;
 
-        let temporary = config["temporary"].as_bool();
         let path = config["path"].as_str();
         let path = path.map(PathBuf::from);
+        let temporary = config["temporary"].as_bool();
         let cache_capacity = config["cache_capacity"].as_u64();
         let flush_every_ms = config["flush_every_ms"].as_u64();
         let mode = match config["mode"].as_str() {
@@ -70,6 +70,17 @@ impl FromStr for PmtreeConfig {
         };
         let use_compression = config["use_compression"].as_bool();
 
+        if temporary.is_some()
+            && path.is_some()
+            && temporary.unwrap()
+            && path.as_ref().unwrap().exists()
+        {
+            return Err(Report::msg(format!(
+                "Path {:?} already exists, cannot use temporary",
+                path.unwrap()
+            )));
+        }
+
         let config = pm_tree::Config::new()
             .temporary(temporary.unwrap_or(get_tmp()))
             .path(path.unwrap_or(get_tmp_path()))