diff --git a/services/web/scripts/remove_duplicate_v1_ids.js b/services/web/scripts/remove_duplicate_v1_ids.js
new file mode 100644
index 0000000000..f45c741a0d
--- /dev/null
+++ b/services/web/scripts/remove_duplicate_v1_ids.js
@@ -0,0 +1,59 @@
+const { db } = require('../app/js/infrastructure/mongojs')
+const async = require('async')
+const minimist = require('minimist')
+
+const argv = minimist(process.argv.slice(2))
+const commit = argv.commit !== undefined
+
+if (!commit) {
+  console.log('DOING DRY RUN. TO SAVE CHANGES PASS --commit')
+}
+
+db.users.aggregate(
+  [
+    { $match: { 'overleaf.id': { $exists: true } } },
+    { $group: { _id: '$overleaf.id', count: { $sum: 1 } } },
+    { $match: { count: { $gt: 1 } } }
+  ],
+  { allowDiskUse: true },
+  function(err, results) {
+    if (err) throw err
+    console.log('FOUND ' + results.length + ' DUPLICATES')
+    async.mapSeries(results, removeDuplicates, function(err) {
+      if (err) throw err
+      console.log('DONE')
+      process.exit()
+    })
+  }
+)
+
+function removeDuplicates(duplicate, callback) {
+  db.users.findOne({ 'overleaf.id': duplicate._id }, function(err, keepUser) {
+    if (err) throw err
+    console.log('KEEPING USER ' + keepUser._id + ' FOR OL ' + duplicate._id)
+    db.users.find(
+      { 'overleaf.id': duplicate._id, _id: { $ne: keepUser._id } },
+      function(err, duplicateUsers) {
+        if (err) throw err
+        async.mapSeries(
+          duplicateUsers,
+          function(user, cb) {
+            console.log(
+              'UNLINKING USER ' + user._id + ' FOR OL ' + duplicate._id
+            )
+            if (!commit) return cb()
+            db.users.update(
+              { _id: user._id },
+              { $unset: { 'overleaf.id': '' } },
+              cb
+            )
+          },
+          function(err) {
+            if (err) throw err
+            callback()
+          }
+        )
+      }
+    )
+  })
+}