diff --git a/apps/files_sharing/appinfo/update.php b/apps/files_sharing/appinfo/update.php
index ee6482d00c..d754a95705 100644
--- a/apps/files_sharing/appinfo/update.php
+++ b/apps/files_sharing/appinfo/update.php
@@ -28,6 +28,7 @@ $installedVersion = \OC::$server->getConfig()->getAppValue('files_sharing', 'ins
 if (version_compare($installedVersion, '0.9.0', '<')) {
 	$m = new Migration(\OC::$server->getDatabaseConnection());
 	$m->removeReShares();
+	$m->updateInitiatorInfo();
 }
 
 \OC::$server->getJobList()->add('OCA\Files_sharing\Lib\DeleteOrphanedSharesJob');
diff --git a/apps/files_sharing/lib/migration.php b/apps/files_sharing/lib/migration.php
index 4ec411d81d..90e0dead48 100644
--- a/apps/files_sharing/lib/migration.php
+++ b/apps/files_sharing/lib/migration.php
@@ -83,6 +83,29 @@ class Migration {
 		}
 	}
 
+	/**
+	 * update all owner information so that all shares have an owner
+	 * and an initiator for the upgrade from oC 8.2 to 9.0 with the new sharing
+	 */
+	public function updateInitiatorInfo() {
+		while (true) {
+			$shares = $this->getMissingInitiator(1000);
+
+			if (empty($shares)) {
+				break;
+			}
+
+			$owners = [];
+			foreach ($shares as $share) {
+				$owners[$share['id']] = [
+					'owner' => $share['uid_owner'],
+					'initiator' => $share['uid_owner']
+				];
+			}
+			$this->updateOwners($owners);
+		}
+	}
+
 	/**
 	 * find the owner of a re-shared file/folder
 	 *
@@ -146,6 +169,49 @@ class Migration {
 		return $ordered;
 	}
 
+	/**
+	 * Get $n re-shares from the database
+	 *
+	 * @param int $n The max number of shares to fetch
+	 * @return array
+	 */
+	private function getMissingInitiator($n = 1000) {
+		$query = $this->connection->getQueryBuilder();
+		$query->select(['id', 'uid_owner'])
+			->from($this->table)
+			->where($query->expr()->in(
+				'share_type',
+				$query->createNamedParameter(
+					[
+						\OCP\Share::SHARE_TYPE_USER,
+						\OCP\Share::SHARE_TYPE_GROUP,
+						\OCP\Share::SHARE_TYPE_LINK
+					],
+					Connection::PARAM_INT_ARRAY
+				)
+			))
+			->andWhere($query->expr()->in(
+				'item_type',
+				$query->createNamedParameter(
+					['file', 'folder'],
+					Connection::PARAM_STR_ARRAY
+				)
+			))
+			->andWhere($query->expr()->isNull('uid_initiator'))
+			->orderBy('id', 'asc')
+			->setMaxResults($n);
+		$result = $query->execute();
+		$shares = $result->fetchAll();
+		$result->closeCursor();
+
+		$ordered = [];
+		foreach ($shares as $share) {
+			$ordered[(int)$share['id']] = $share;
+		}
+
+		return $ordered;
+	}
+
 	/**
 	 * get a specific share
 	 *
diff --git a/apps/files_sharing/tests/migrationtest.php b/apps/files_sharing/tests/migrationtest.php
index fb9d1242ac..e1c047e034 100644
--- a/apps/files_sharing/tests/migrationtest.php
+++ b/apps/files_sharing/tests/migrationtest.php
@@ -246,9 +246,9 @@ class MigrationTest extends TestCase {
 		}
 	}
 
-	public function test100kDeepReshares() {
+	public function test1001DeepReshares() {
 		$parent = null;
-		for ($i = 0; $i < 10; $i++) {
+		for ($i = 0; $i < 1001; $i++) {
 			$query = $this->connection->getQueryBuilder();
 			$query->insert($this->table)
 				->values(
@@ -270,7 +270,7 @@ class MigrationTest extends TestCase {
 				->setParameter('share_type', \OCP\Share::SHARE_TYPE_USER)
 				->setParameter('share_with', 'user'.($i+1))
 				->setParameter('uid_owner', 'user'.($i))
-				->setParameter('uid_initiator', '')
+				->setParameter('uid_initiator', null)
 				->setParameter('parent', $parent)
 				->setParameter('item_type', 'file')
 				->setParameter('item_source', '2')
@@ -285,6 +285,7 @@ class MigrationTest extends TestCase {
 		}
 
 		$this->migration->removeReShares();
+		$this->migration->updateInitiatorInfo();
 
 		$qb = $this->connection->getQueryBuilder();
 
@@ -296,13 +297,12 @@ class MigrationTest extends TestCase {
 		$i = 0;
 		while($share = $stmt->fetch()) {
 			$this->assertEquals('user'.($i+1), $share['share_with']);
-			if ($i !== 0) {
-				$this->assertEquals('user' . ($i), $share['uid_initiator']);
-				$this->assertEquals('user0', $share['uid_owner']);
-			}
+			$this->assertEquals('user' . ($i), $share['uid_initiator']);
+			$this->assertEquals('user0', $share['uid_owner']);
 			$this->assertEquals(null, $share['parent']);
 			$i++;
 		}
 		$stmt->closeCursor();
+		$this->assertEquals(1001, $i);
 	}
 }