diff --git a/cmdline/cmdline.c b/cmdline/cmdline.c
index 54e0ca38..3b85710e 100644
--- a/cmdline/cmdline.c
+++ b/cmdline/cmdline.c
@@ -102,7 +102,7 @@ static int mrmailbox_cleanup_contacts(mrmailbox_t* ths)
 
 	mrsqlite3_lock(ths->m_sql);
 
-	mrsqlite3_execute__(ths->m_sql, "DELETE FROM contacts WHERE id>" MR_STRINGIFY(MR_CONTACT_ID_LAST_SPECIAL) " AND blocked=0 AND NOT EXISTS (SELECT contact_id FROM chats_contacts where contacts.id = chats_contacts.contact_id) AND NOT EXISTS (select from_id from msgs WHERE msgs.from_id = contacts.id);");
+		mrsqlite3_execute__(ths->m_sql, "DELETE FROM contacts WHERE id>" MR_STRINGIFY(MR_CONTACT_ID_LAST_SPECIAL) " AND blocked=0 AND NOT EXISTS (SELECT contact_id FROM chats_contacts where contacts.id = chats_contacts.contact_id) AND NOT EXISTS (select from_id from msgs WHERE msgs.from_id = contacts.id);");
 
 	mrsqlite3_unlock(ths->m_sql);
 
@@ -273,14 +273,10 @@ static int poke_spec(mrmailbox_t* mailbox, const char* spec)
 		mailbox->m_cb(mailbox, MR_EVENT_MSGS_CHANGED, 0, 0); /* even if read_cnt>0, the number of messages added to the database may be 0. While we regard this issue using IMAP, we ignore it here. */
 	}
 
-	/* success */
 	success = 1;
 
-	/* cleanup */
 cleanup:
-	if( dir ) {
-		closedir(dir);
-	}
+	if( dir ) { closedir(dir); }
 	free(real_spec);
 	free(suffix);
 	return success;
diff --git a/src/mrcontact.c b/src/mrcontact.c
index 23f89846..bc281924 100644
--- a/src/mrcontact.c
+++ b/src/mrcontact.c
@@ -404,10 +404,8 @@ int mrcontact_load_from_db__(mrcontact_t* ths, mrsqlite3_t* sql, uint32_t contac
 		ths->m_authname         = safe_strdup((char*)sqlite3_column_text (stmt, 4));
 	}
 
-	/* success */
 	success = 1;
 
-	/* cleanup */
 cleanup:
 	return success;
 }
diff --git a/src/mrevent.h b/src/mrevent.h
index 6e45b9b2..2248fb58 100644
--- a/src/mrevent.h
+++ b/src/mrevent.h
@@ -269,7 +269,7 @@ extern "C" {
  * Acquire or release a wakelock.
  *
  * The core surrounds critical functions that should not be killed by the operating system with wakelocks.
- * Before a critical function _MR_EVENT_WAKE_LOCK with data1=1_ is called, it it finishes, _MR_EVENT_WAKE_LOCK with data1=0_ is called.
+ * Before a critical function _MR_EVENT_WAKE_LOCK with data1=1_ is called, when it finishes, _MR_EVENT_WAKE_LOCK with data1=0_ is called.
  * If you do not need this functionality, just ignore this event.
  *
  * @param data1 1=acquire wakelock, 0=release wakelock, the core does not make nested or unsynchronized calls
diff --git a/src/mrmailbox.c b/src/mrmailbox.c
index a57cb528..5a8a408a 100644
--- a/src/mrmailbox.c
+++ b/src/mrmailbox.c
@@ -247,45 +247,40 @@ int mrmailbox_open(mrmailbox_t* mailbox, const char* dbfile, const char* blobdir
 	mrsqlite3_lock(mailbox->m_sql);
 	db_locked = 1;
 
-	/* Open() sets up the object and connects to the given database
-	from which all configuration is read/written to. */
+		/* Open() sets up the object and connects to the given database
+		from which all configuration is read/written to. */
 
-	/* Create/open sqlite database */
-	if( !mrsqlite3_open__(mailbox->m_sql, dbfile, 0) ) {
-		goto cleanup;
-	}
-	mrjob_kill_action__(mailbox, MRJ_CONNECT_TO_IMAP);
-
-	/* backup dbfile name */
-	mailbox->m_dbfile = safe_strdup(dbfile);
-
-	/* set blob-directory
-	(to avoid double slashed, the given directory should not end with an slash) */
-	if( blobdir && blobdir[0] ) {
-		mailbox->m_blobdir = safe_strdup(blobdir);
-	}
-	else {
-		mailbox->m_blobdir = mr_mprintf("%s-blobs", dbfile);
-		mr_create_folder(mailbox->m_blobdir, mailbox);
-	}
-
-	/* cache some settings */
-	update_config_cache__(mailbox, NULL);
-
-	/* success */
-	success = 1;
-
-	/* cleanup */
-cleanup:
-	if( !success ) {
-		if( mrsqlite3_is_open(mailbox->m_sql) ) {
-			mrsqlite3_close__(mailbox->m_sql);
+		/* Create/open sqlite database */
+		if( !mrsqlite3_open__(mailbox->m_sql, dbfile, 0) ) {
+			goto cleanup;
 		}
-	}
+		mrjob_kill_action__(mailbox, MRJ_CONNECT_TO_IMAP);
 
-	if( db_locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+		/* backup dbfile name */
+		mailbox->m_dbfile = safe_strdup(dbfile);
+
+		/* set blob-directory
+		(to avoid double slashed, the given directory should not end with an slash) */
+		if( blobdir && blobdir[0] ) {
+			mailbox->m_blobdir = safe_strdup(blobdir);
+		}
+		else {
+			mailbox->m_blobdir = mr_mprintf("%s-blobs", dbfile);
+			mr_create_folder(mailbox->m_blobdir, mailbox);
+		}
+
+		update_config_cache__(mailbox, NULL);
+
+		success = 1;
+
+cleanup:
+		if( !success ) {
+			if( mrsqlite3_is_open(mailbox->m_sql) ) {
+				mrsqlite3_close__(mailbox->m_sql);
+			}
+		}
+
+	if( db_locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 
 	return success;
 }
@@ -404,8 +399,10 @@ int mrmailbox_set_config(mrmailbox_t* ths, const char* key, const char* value)
 	}
 
 	mrsqlite3_lock(ths->m_sql);
+
 		ret = mrsqlite3_set_config__(ths->m_sql, key, value);
 		update_config_cache__(ths, key);
+
 	mrsqlite3_unlock(ths->m_sql);
 
 	return ret;
@@ -435,7 +432,9 @@ char* mrmailbox_get_config(mrmailbox_t* ths, const char* key, const char* def)
 	}
 
 	mrsqlite3_lock(ths->m_sql);
+
 		ret = mrsqlite3_get_config__(ths->m_sql, key, def);
+
 	mrsqlite3_unlock(ths->m_sql);
 
 	return ret; /* the returned string must be free()'d, returns NULL only if "def" is NULL and "key" is unset */
@@ -457,8 +456,10 @@ int mrmailbox_set_config_int(mrmailbox_t* ths, const char* key, int32_t value)
 	}
 
 	mrsqlite3_lock(ths->m_sql);
+
 		ret = mrsqlite3_set_config_int__(ths->m_sql, key, value);
 		update_config_cache__(ths, key);
+
 	mrsqlite3_unlock(ths->m_sql);
 
 	return ret;
@@ -479,7 +480,9 @@ int32_t mrmailbox_get_config_int(mrmailbox_t* ths, const char* key, int32_t def)
 	}
 
 	mrsqlite3_lock(ths->m_sql);
+
 		ret = mrsqlite3_get_config_int__(ths->m_sql, key, def);
+
 	mrsqlite3_unlock(ths->m_sql);
 
 	return ret;
@@ -728,13 +731,8 @@ void mrmailbox_connect_to_imap(mrmailbox_t* ths, mrjob_t* job /*may be NULL if t
 	}
 
 cleanup:
-	if( param ) {
-		mrloginparam_unref(param);
-	}
-
-	if( is_locked ) {
-		mrsqlite3_unlock(ths->m_sql);
-	}
+	if( is_locked ) { mrsqlite3_unlock(ths->m_sql); }
+	mrloginparam_unref(param);
 }
 
 
@@ -782,7 +780,9 @@ void mrmailbox_disconnect(mrmailbox_t* mailbox)
 	}
 
 	mrsqlite3_lock(mailbox->m_sql);
+
 		mrjob_kill_action__(mailbox, MRJ_CONNECT_TO_IMAP);
+
 	mrsqlite3_unlock(mailbox->m_sql);
 
 	mrimap_disconnect(mailbox->m_imap);
@@ -845,19 +845,14 @@ mrchatlist_t* mrmailbox_get_chatlist(mrmailbox_t* mailbox, int listflags, const
 	mrsqlite3_lock(mailbox->m_sql);
 	db_locked = 1;
 
-	if( !mrchatlist_load_from_db__(obj, listflags, query) ) {
-		goto cleanup;
-	}
+		if( !mrchatlist_load_from_db__(obj, listflags, query) ) {
+			goto cleanup;
+		}
 
-	/* success */
+		success = 1;
 
-	success = 1;
-
-	/* cleanup */
 cleanup:
-	if( db_locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( db_locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 
 	if( success ) {
 		return obj;
@@ -893,18 +888,14 @@ mrchat_t* mrmailbox_get_chat(mrmailbox_t* mailbox, uint32_t chat_id)
 	mrsqlite3_lock(mailbox->m_sql);
 	db_locked = 1;
 
-	if( !mrchat_load_from_db__(obj, chat_id) ) {
-		goto cleanup;
-	}
+		if( !mrchat_load_from_db__(obj, chat_id) ) {
+			goto cleanup;
+		}
 
-	/* success */
-	success = 1;
+		success = 1;
 
-	/* cleanup */
 cleanup:
-	if( db_locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( db_locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 
 	if( success ) {
 		return obj;
@@ -1159,7 +1150,9 @@ mrarray_t* mrmailbox_get_chat_media(mrmailbox_t* mailbox, uint32_t chat_id, int
 	}
 
 	mrsqlite3_lock(mailbox->m_sql);
+
 		ret = mrmailbox_get_chat_media__(mailbox, chat_id, msg_type, or_msg_type);
+
 	mrsqlite3_unlock(mailbox->m_sql);
 
 	return ret;
@@ -1233,7 +1226,7 @@ uint32_t mrmailbox_get_next_media(mrmailbox_t* mailbox, uint32_t curr_msg_id, in
 
 cleanup:
 	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
-	if( list ) { mrarray_unref(list); }
+	mrarray_unref(list);
 	mrmsg_unref(msg);
 	return ret_msg_id;
 }
@@ -1338,9 +1331,7 @@ mrarray_t* mrmailbox_get_fresh_msgs(mrmailbox_t* mailbox)
 	success = 1;
 
 cleanup:
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 
 	if( success ) {
 		return ret;
@@ -1452,9 +1443,7 @@ mrarray_t* mrmailbox_get_chat_msgs(mrmailbox_t* mailbox, uint32_t chat_id, uint3
 	success = 1;
 
 cleanup:
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 
 	if( success ) {
 		return ret;
@@ -1555,9 +1544,7 @@ mrarray_t* mrmailbox_search_msgs(mrmailbox_t* mailbox, uint32_t chat_id, const c
 	success = 1;
 
 cleanup:
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 	free(strLikeInText);
 	free(strLikeBeg);
 	free(real_query);
@@ -3133,7 +3120,9 @@ int mrmailbox_is_contact_in_chat(mrmailbox_t* mailbox, uint32_t chat_id, uint32_
 	}
 
 	mrsqlite3_lock(mailbox->m_sql);
+
 		ret = mrmailbox_is_contact_in_chat__(mailbox, chat_id, contact_id);
+
 	mrsqlite3_unlock(mailbox->m_sql);
 
 	return ret;
@@ -3720,12 +3709,8 @@ mrarray_t* mrmailbox_get_known_contacts(mrmailbox_t* mailbox, const char* query)
 	}
 
 cleanup:
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
-	if( s3strLikeCmd ) {
-		sqlite3_free(s3strLikeCmd);
-	}
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
+	if( s3strLikeCmd ) { sqlite3_free(s3strLikeCmd); }
 	free(self_addr);
 	free(self_name);
 	free(self_name2);
@@ -3868,7 +3853,9 @@ void mrmailbox_marknoticed_contact(mrmailbox_t* mailbox, uint32_t contact_id)
 		return;
     }
     mrsqlite3_lock(mailbox->m_sql);
+
 		marknoticed_contact__(mailbox, contact_id);
+
     mrsqlite3_unlock(mailbox->m_sql);
 }
 
@@ -3967,14 +3954,8 @@ void mrmailbox_block_contact(mrmailbox_t* mailbox, uint32_t contact_id, int new_
 	}
 
 cleanup:
-	if( transaction_pending ) {
-		mrsqlite3_rollback__(mailbox->m_sql);
-	}
-
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
-
+	if( transaction_pending ) { mrsqlite3_rollback__(mailbox->m_sql); }
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 	mrcontact_unref(contact);
 }
 
@@ -4179,9 +4160,7 @@ int mrmailbox_delete_contact(mrmailbox_t* mailbox, uint32_t contact_id)
 	success = 1;
 
 cleanup:
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 	return success;
 }
 
@@ -4349,9 +4328,7 @@ mrmsg_t* mrmailbox_get_msg(mrmailbox_t* mailbox, uint32_t msg_id)
 		success = 1;
 
 cleanup:
-	if( db_locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( db_locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 
 	if( success ) {
 		return obj;
@@ -4708,9 +4685,7 @@ void mrmailbox_delete_msg_on_imap(mrmailbox_t* mailbox, mrjob_t* job)
 	locked = 0;
 
 cleanup:
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 	mrmsg_unref(msg);
 }
 
@@ -4820,9 +4795,7 @@ void mrmailbox_markseen_msg_on_imap(mrmailbox_t* mailbox, mrjob_t* job)
 	}
 
 cleanup:
-	if( locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
+	if( locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 	mrmsg_unref(msg);
 	free(new_server_folder);
 }
@@ -5023,7 +4996,8 @@ void mrmailbox_send_mdn(mrmailbox_t* mailbox, mrjob_t* job)
 	}
 
 	/* connect to SMTP server, if not yet done */
-	if( !mrsmtp_is_connected(mailbox->m_smtp) ) {
+	if( !mrsmtp_is_connected(mailbox->m_smtp) )
+	{
 		mrloginparam_t* loginparam = mrloginparam_new();
 			mrsqlite3_lock(mailbox->m_sql);
 				mrloginparam_read__(loginparam, mailbox->m_sql, "configured_");
diff --git a/src/mrmailbox_receive_imf.c b/src/mrmailbox_receive_imf.c
index b08d1862..0304416a 100644
--- a/src/mrmailbox_receive_imf.c
+++ b/src/mrmailbox_receive_imf.c
@@ -863,27 +863,26 @@ void mrmailbox_receive_imf(mrmailbox_t* mailbox, const char* imf_raw_not_termina
 		goto cleanup; /* Error - even adding an empty record won't help as we do not know the message ID */
 	}
 
+	/* Check, if the mail comes from extern, resp. is not sent by us.  This is a _really_ important step
+	as messages sent by us are used to validate other mail senders and receivers.
+	For this purpose, we assume, the `Return-Path:`-header is never present if the message is sent by us.
+	The `Received:`-header may be another idea, however, this is also set if mails are transfered from other accounts via IMAP.
+	Using `From:` alone is no good idea, as mailboxes may use different sending-addresses - moreover, they may change over the years.
+	However, we use `From:` as an additional hint below. */
+	if( mrmimeparser_lookup_field(mime_parser, "Return-Path") ) {
+		has_return_path = 1;
+	}
+
+	if( has_return_path ) {
+		incoming = 1;
+	}
+
 	mrsqlite3_lock(mailbox->m_sql);
 	db_locked = 1;
-
 	mrsqlite3_begin_transaction__(mailbox->m_sql);
 	transaction_pending = 1;
 
 
-		/* Check, if the mail comes from extern, resp. is not sent by us.  This is a _really_ important step
-		as messages sent by us are used to validate other mail senders and receivers.
-		For this purpose, we assume, the `Return-Path:`-header is never present if the message is sent by us.
-		The `Received:`-header may be another idea, however, this is also set if mails are transfered from other accounts via IMAP.
-		Using `From:` alone is no good idea, as mailboxes may use different sending-addresses - moreover, they may change over the years.
-		However, we use `From:` as an additional hint below. */
-		if( mrmimeparser_lookup_field(mime_parser, "Return-Path") ) {
-			has_return_path = 1;
-		}
-
-		if( has_return_path ) {
-			incoming = 1;
-		}
-
 		/* for incoming messages, get From: and check if it is known (for known From:'s we add the other To:/Cc:/Bcc: in the 3rd pass) */
 		if( incoming
 		 && (field=mrmimeparser_lookup_field(mime_parser, "From"))!=NULL
@@ -1322,31 +1321,17 @@ void mrmailbox_receive_imf(mrmailbox_t* mailbox, const char* imf_raw_not_termina
 			free(emlname);
 		}
 
-	/* end sql-transaction */
+
 	mrsqlite3_commit__(mailbox->m_sql);
 	transaction_pending = 0;
 
-	/* done */
 cleanup:
-	if( transaction_pending ) {
-		mrsqlite3_rollback__(mailbox->m_sql);
-	}
+	if( transaction_pending ) { mrsqlite3_rollback__(mailbox->m_sql); }
+	if( db_locked ) { mrsqlite3_unlock(mailbox->m_sql); }
 
-	if( db_locked ) {
-		mrsqlite3_unlock(mailbox->m_sql);
-	}
-
-	if( mime_parser ) {
-		mrmimeparser_unref(mime_parser);
-	}
-
-	if( rfc724_mid ) {
-		free(rfc724_mid);
-	}
-
-	if( to_ids ) {
-		mrarray_unref(to_ids);
-	}
+	mrmimeparser_unref(mime_parser);
+	free(rfc724_mid);
+	mrarray_unref(to_ids);
 
 	if( created_db_entries ) {
 		if( create_event_to_send ) {
diff --git a/src/mrmimefactory.c b/src/mrmimefactory.c
index e87b8f6d..5f98d359 100644
--- a/src/mrmimefactory.c
+++ b/src/mrmimefactory.c
@@ -223,6 +223,7 @@ int mrmimefactory_load_msg(mrmimefactory_t* factory, uint32_t msg_id)
 		if( success ) {
 			factory->m_increation = mrmsg_is_increation__(factory->m_msg);
 		}
+
 	mrsqlite3_unlock(mailbox->m_sql);
 	locked = 0;
 
diff --git a/src/mrmsg.c b/src/mrmsg.c
index 7722a3b4..71214751 100644
--- a/src/mrmsg.c
+++ b/src/mrmsg.c
@@ -1090,17 +1090,21 @@ int mrmsg_is_increation__(const mrmsg_t* msg)
 int mrmsg_is_increation(mrmsg_t* msg)
 {
 	/* surrounds mrmsg_is_increation__() with locking and error checking */
+	int is_increation = 0;
+
 	if( msg == NULL || msg->m_magic != MR_MSG_MAGIC ) {
 		return 0;
 	}
 
-	int is_increation = 0;
 	if( msg->m_mailbox && MR_MSG_NEEDS_ATTACHMENT(msg->m_type) /*additional check for speed reasons*/ )
 	{
 		mrsqlite3_lock(msg->m_mailbox->m_sql);
+
 			is_increation = mrmsg_is_increation__(msg);
+
 		mrsqlite3_unlock(msg->m_mailbox->m_sql);
 	}
+
 	return is_increation;
 }