diff --git a/plume-models/plume.db-journal b/plume-models/plume.db-journal
new file mode 100644
index 00000000..2a40935d
Binary files /dev/null and b/plume-models/plume.db-journal differ
diff --git a/plume-models/plume_tests.sqlite-journal b/plume-models/plume_tests.sqlite-journal
new file mode 100644
index 00000000..624b437f
Binary files /dev/null and b/plume-models/plume_tests.sqlite-journal differ
diff --git a/plume-models/src/search/searcher.rs b/plume-models/src/search/searcher.rs
index a1f4c813..34a45b0b 100644
--- a/plume-models/src/search/searcher.rs
+++ b/plume-models/src/search/searcher.rs
@@ -5,10 +5,10 @@ use crate::{
 use chrono::Datelike;
 use diesel::{ExpressionMethods, QueryDsl, RunQueryDsl};
 use itertools::Itertools;
-use std::{cmp, fs::create_dir_all, path::Path, sync::Mutex};
+use std::{cmp, fs::create_dir_all, io, path::Path, sync::Mutex};
 use tantivy::{
     collector::TopDocs, directory::MmapDirectory, schema::*, Index, IndexReader, IndexWriter,
-    ReloadPolicy, Term,
+    ReloadPolicy, TantivyError, Term,
 };
 use whatlang::{detect as detect_lang, Lang};
 
@@ -18,6 +18,7 @@ pub enum SearcherError {
     WriteLockAcquisitionError,
     IndexOpeningError,
     IndexEditionError,
+    InvalidIndexDataError,
 }
 
 pub struct Searcher {
@@ -135,7 +136,19 @@ impl Searcher {
                 .reader_builder()
                 .reload_policy(ReloadPolicy::Manual)
                 .try_into()
-                .map_err(|_| SearcherError::IndexCreationError)?,
+                .map_err(|e| {
+                    if let TantivyError::IOError(err) = e {
+                        let err: io::Error = err.into();
+                        if err.kind() == io::ErrorKind::InvalidData {
+                            // Search index was created in older Tantivy format.
+                            SearcherError::InvalidIndexDataError
+                        } else {
+                            SearcherError::IndexCreationError
+                        }
+                    } else {
+                        SearcherError::IndexCreationError
+                    }
+                })?,
             index,
         })
     }
diff --git a/src/main.rs b/src/main.rs
old mode 100644
new mode 100755
index e52fde7b..4ae2f88f
--- a/src/main.rs
+++ b/src/main.rs
@@ -10,6 +10,7 @@ extern crate serde_json;
 #[macro_use]
 extern crate validator_derive;
 
+use chrono::Utc;
 use clap::App;
 use diesel::r2d2::ConnectionManager;
 use plume_models::{
@@ -21,6 +22,8 @@ use plume_models::{
 };
 use rocket_csrf::CsrfFairingBuilder;
 use scheduled_thread_pool::ScheduledThreadPool;
+use std::fs;
+use std::path::Path;
 use std::process::exit;
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
@@ -98,8 +101,30 @@ Then try to restart Plume.
     }
     let workpool = ScheduledThreadPool::with_name("worker {}", num_cpus::get());
     // we want a fast exit here, so
+    let mut open_searcher =
+        UnmanagedSearcher::open(&CONFIG.search_index, &CONFIG.search_tokenizers);
+    if let Err(Error::Search(SearcherError::InvalidIndexDataError)) = open_searcher {
+        if UnmanagedSearcher::create(&CONFIG.search_index, &CONFIG.search_tokenizers).is_err() {
+            let current_path = Path::new(&CONFIG.search_index);
+            let backup_path = format!("{}.{}", &current_path.display(), Utc::now().timestamp());
+            let backup_path = Path::new(&backup_path);
+            fs::rename(current_path, backup_path)
+                .expect("main: error on backing up search index directory for recreating");
+            if UnmanagedSearcher::create(&CONFIG.search_index, &CONFIG.search_tokenizers).is_ok() {
+                if fs::remove_dir_all(backup_path).is_err() {
+                    eprintln!(
+                        "error on removing backup directory: {}. it remains",
+                        backup_path.display()
+                    );
+                }
+            } else {
+                panic!("main: error on recreating search index in new index format. remove search index and run `plm search init` manually");
+            }
+        }
+        open_searcher = UnmanagedSearcher::open(&CONFIG.search_index, &CONFIG.search_tokenizers);
+    }
     #[allow(clippy::match_wild_err_arm)]
-    let searcher = match UnmanagedSearcher::open(&CONFIG.search_index, &CONFIG.search_tokenizers) {
+    let searcher = match open_searcher {
         Err(Error::Search(e)) => match e {
             SearcherError::WriteLockAcquisitionError => panic!(
                 r#"