diff --git a/lib/Cache/Cache.php b/lib/Cache/Cache.php
index e4cc808b1d..08bad94848 100644
--- a/lib/Cache/Cache.php
+++ b/lib/Cache/Cache.php
@@ -59,13 +59,15 @@ public function getCachedUids($mailbox, $uidvalid) {
 		}
 
 		// Refresh cached uids lazily
-		if ($cachedMailbox->getUids() === null) {
+		$cachedUids = $cachedMailbox->getUids();
+		if ($cachedUids === null) {
 			$mailboxEntity = $this->mailboxMapper->find($this->account, $mailbox);
-			$cachedMailbox->setUids($this->dbMessageMapper->findAllUids($mailboxEntity));
+			$cachedUids = $this->dbMessageMapper->findAllUids($mailboxEntity);
+			$cachedMailbox->setUids($cachedUids);
 		}
 
-		// Copy the array as we don't know whether horde will mutate it
-		return array_merge([], $cachedMailbox->getUids());
+		// Copy the array because we don't know whether horde will mutate it
+		return array_merge([], $cachedUids);
 	}
 
 	public function set($mailbox, $data, $uidvalid) {
@@ -107,53 +109,23 @@ public function getMetaData($mailbox, $uidvalid, $entries) {
 	public function setMetaData($mailbox, $data) {
 		// Don't mutate any metadata.
 		// The data will be refreshed once the new sync token is written to the db.
-
-		/*
-		$knownUidvalid = null;
-		$knownHighestmodseq = null;
-
-		if (isset($this->uidvalid[$mailbox])) {
-			$knownUidvalid = $this->uidvalid[$mailbox];
-		}
-		if (isset($this->highestmodseq[$mailbox])) {
-			$knownHighestmodseq = $this->highestmodseq[$mailbox];
-		}
-
-		$uidvalid = null;
-		if (isset($data['uidvalid'])) {
-			$uidvalid = (int)$data['uidvalid'];
-		}
-
-		if ($knownUidvalid === null && $uidvalid !== null) {
-			$this->uidvalid[$mailbox] = $uidvalid;
-		} elseif ($knownUidvalid !== null && $uidvalid !== null && $knownUidvalid !== $uidvalid) {
-			$this->deleteMailbox($mailbox);
-			$this->uidvalid[$mailbox] = $uidvalid;
-			//unset($this->cachedUids[$mailbox]);
-		}
-
-		if (isset($data['_m'])) {
-			var_dump('New _m', $data['_m']);
-			$this->highestmodseq[$mailbox] = (int)$data['_m'];
-		}
-
-		$data2 = array_merge([], $data);
-		unset($data2['uidvalid'], $data2['_m']);
-		if (!isset($this->cache[$mailbox])) {
-			$this->cache[$mailbox] = [];
-		}
-		foreach ($data2 as $key => $value) {
-			$this->cache[$mailbox][$key] = $value;
-		}
-		*/
 	}
 
 	public function deleteMsgs($mailbox, $uids) {
 		$mailboxEntity = $this->mailboxMapper->find($this->account, $mailbox);
 		$this->dbMessageMapper->deleteByUid($mailboxEntity, ...$uids);
-		if (isset($this->cachedUids[$mailbox])) {
-			$this->cachedUids[$mailbox] = array_diff($this->cachedUids[$mailbox], $uids);
+
+		if (!isset($this->cachedMailboxes[$mailbox])) {
+			return;
+		}
+
+		$cachedMailbox = $this->cachedMailboxes[$mailbox];
+		$cachedUids = $cachedMailbox->getUids();
+		if ($cachedUids === null) {
+			return;
 		}
+
+		$cachedMailbox->setUids(array_diff($cachedUids, $uids));
 	}
 
 	public function deleteMailbox($mailbox) {
@@ -161,7 +133,6 @@ public function deleteMailbox($mailbox) {
 	}
 
 	public function clear($lifetime) {
-		// Clear all data cached in memory to trigger a refetch from the db on the next access
 		$this->cachedMailboxes = [];
 	}
 }