diff --git a/services/web/app/coffee/Features/ThirdPartyDataStore/UpdateMerger.coffee b/services/web/app/coffee/Features/ThirdPartyDataStore/UpdateMerger.coffee
index 887168fc9e..d05443b6e9 100644
--- a/services/web/app/coffee/Features/ThirdPartyDataStore/UpdateMerger.coffee
+++ b/services/web/app/coffee/Features/ThirdPartyDataStore/UpdateMerger.coffee
@@ -6,26 +6,35 @@ Settings = require('settings-sharelatex')
 FileTypeManager = require('../Uploads/FileTypeManager')
 uuid = require('node-uuid')
 fs = require('fs')
+LockManager = require("../../infrastructure/LockManager")
+
 
 module.exports =
 	mergeUpdate: (project_id, path, updateRequest, source, callback = (error) ->)->
 		self = @
 		logger.log project_id:project_id, path:path, "merging update from tpds"
-		projectLocator.findElementByPath project_id, path, (err, element)=>
-			# Returns an error if the element is not found
-			#return callback(err) if err?
-			logger.log project_id:project_id, path:path, "found element by path for merging update from tpds"
-			elementId = undefined
-			if element?
-				elementId = element._id
-			self.p.writeStreamToDisk project_id, elementId, updateRequest, (err, fsPath)->
-				return callback(err) if err?
-				FileTypeManager.isBinary path, fsPath, (err, isFile)->
+		LockManager.getLock project_id, (err)->
+			if err?
+				logger.err project_id:project_id, "could not get lock for merge update"
+				return callback()
+			projectLocator.findElementByPath project_id, path, (err, element)=>
+				# Returns an error if the element is not found
+				#return callback(err) if err?
+				logger.log project_id:project_id, path:path, "found element by path for merging update from tpds"
+				elementId = undefined
+				if element?
+					elementId = element._id
+				self.p.writeStreamToDisk project_id, elementId, updateRequest, (err, fsPath)->
 					return callback(err) if err?
-					if isFile
-						self.p.processFile project_id, elementId, fsPath, path, source, callback #TODO clean up the stream written to disk here
-					else
-						self.p.processDoc project_id, elementId, fsPath, path, source, callback
+					FileTypeManager.isBinary path, fsPath, (err, isFile)->
+						return callback(err) if err?
+						finish = (err)->
+							LockManager.releaseLock project_id, ->
+								callback(err)
+						if isFile
+							self.p.processFile project_id, elementId, fsPath, path, source, finish #TODO clean up the stream written to disk here
+						else
+							self.p.processDoc project_id, elementId, fsPath, path, source, finish
 
 	deleteUpdate: (project_id, path, source, callback)->
 		projectLocator.findElementByPath project_id, path, (err, element)->
@@ -38,7 +47,7 @@ module.exports =
 			else if element.folders?
 				type = 'folder'
 			logger.log project_id:project_id, updateType:path, updateType:type, element:element, "processing update to delete entity from tpds"
-			editorController.deleteEntity project_id, element._id, type, source, (err)->
+			editorController.deleteEntityWithoutLock project_id, element._id, type, source, (err)->
 				logger.log project_id:project_id, path:path, "finished processing update to delete entity from tpds"
 				callback()
 
@@ -55,7 +64,7 @@ module.exports =
 						callback()
 				else
 					setupNewEntity project_id, path, (err, folder, fileName)->
-						editorController.addDoc project_id, folder._id, fileName, docLines, source, (err)->
+						editorController.addDocWithoutLock project_id, folder._id, fileName, docLines, source, (err)->
 							callback()
 
 		processFile: (project_id, file_id, fsPath, path, source, callback)->
@@ -67,7 +76,7 @@ module.exports =
 				if file_id?
 					editorController.replaceFile project_id, file_id, fsPath, source, finish
 				else
-					editorController.addFile project_id, folder._id, fileName, fsPath, source, finish
+					editorController.addFileWithoutLock project_id, folder._id, fileName, fsPath, source, finish
 
 		writeStreamToDisk: (project_id, file_id, stream, callback = (err, fsPath)->)->
 			if !file_id?
@@ -103,5 +112,5 @@ setupNewEntity = (project_id, path, callback)->
 	lastIndexOfSlash = path.lastIndexOf("/")
 	fileName = path[lastIndexOfSlash+1 .. -1]
 	folderPath = path[0 .. lastIndexOfSlash]
-	editorController.mkdirp project_id, folderPath, (err, newFolders, lastFolder)->
+	editorController.mkdirpWithoutLock project_id, folderPath, (err, newFolders, lastFolder)->
 		callback err, lastFolder, fileName
diff --git a/services/web/test/UnitTests/coffee/ThirdPartyDataStore/UpdateMergerTests.coffee b/services/web/test/UnitTests/coffee/ThirdPartyDataStore/UpdateMergerTests.coffee
index 61ff8da023..4785a0517e 100644
--- a/services/web/test/UnitTests/coffee/ThirdPartyDataStore/UpdateMergerTests.coffee
+++ b/services/web/test/UnitTests/coffee/ThirdPartyDataStore/UpdateMergerTests.coffee
@@ -13,12 +13,16 @@ describe 'UpdateMerger :', ->
 		@projectEntityHandler = {}
 		@fs = {}
 		@FileTypeManager = {}
+		@LockManager = 
+			getLock:sinon.stub()
+			releaseLock:sinon.stub()
 		@updateMerger = SandboxedModule.require modulePath, requires:
 			'../Editor/EditorController': @editorController
 			'../Project/ProjectLocator': @projectLocator
 			'../Project/ProjectEntityHandler': @projectEntityHandler
 			'fs': @fs
 			'../Uploads/FileTypeManager':@FileTypeManager
+			"../../infrastructure/LockManager": @LockManager
 			'logger-sharelatex':
 				log: ->
 				err: ->
@@ -32,13 +36,17 @@ describe 'UpdateMerger :', ->
 			@path = "/doc1"
 			@fsPath = "file/system/path.tex"
 			@updateMerger.p.writeStreamToDisk = sinon.stub().callsArgWith(3, null, @fsPath)
+			@LockManager.getLock.callsArgWith(1)
+			@LockManager.releaseLock.callsArgWith(1)
 			@FileTypeManager.isBinary = sinon.stub()
 
 		it 'should get the element id', (done)->
-			@projectLocator.findElementByPath = sinon.spy()
+			@projectLocator.findElementByPath = sinon.stub().callsArgWith(2)
+			@FileTypeManager.isBinary.callsArgWith(2, null, false)
+			@updateMerger.p.processDoc = sinon.stub().callsArgWith(5)
 			@updateMerger.mergeUpdate @project_id, @path, @update, @source, =>
-			@projectLocator.findElementByPath.calledWith(@project_id, @path).should.equal true
-			done()
+				@projectLocator.findElementByPath.calledWith(@project_id, @path).should.equal true
+				done()
 
 		it 'should process update as doc when it is a doc', (done)->
 			doc_id = "231312s"
@@ -64,6 +72,16 @@ describe 'UpdateMerger :', ->
 				@FileTypeManager.isBinary.calledWith(filePath, @fsPath).should.equal true
 				done()
 
+		it "should get the lock", (done)->
+
+			@FileTypeManager.isBinary.callsArgWith(2, null, false)
+			@projectLocator.findElementByPath = (_, __, cb)->cb(null, {_id:"doc_id"})
+			@updateMerger.p.processDoc = sinon.stub().callsArgWith(5)
+
+			@updateMerger.mergeUpdate @project_id, @path, @update, @source, =>
+				@LockManager.getLock.calledWith(@project_id).should.equal true
+				done()
+
 
 	describe 'processDoc :', (done)->
 		beforeEach ->
@@ -87,9 +105,9 @@ describe 'UpdateMerger :', ->
 			folder = {_id:"adslkjioj"}
 			docName = "main.tex"
 			path = "folder1/folder2/#{docName}"
-			@editorController.mkdirp = sinon.stub().withArgs(@project_id).callsArgWith(2, null, [folder], folder)
-			@editorController.addDoc = ->
-			mock = sinon.mock(@editorController).expects("addDoc").withArgs(@project_id, folder._id, docName, @splitDocLines, @source).callsArg(5)
+			@editorController.mkdirpWithoutLock = sinon.stub().withArgs(@project_id).callsArgWith(2, null, [folder], folder)
+			@editorController.addDocWithoutLock = ->
+			mock = sinon.mock(@editorController).expects("addDocWithoutLock").withArgs(@project_id, folder._id, docName, @splitDocLines, @source).callsArg(5)
 
 			@update.write(@docLines)
 			@update.end()
@@ -106,22 +124,22 @@ describe 'UpdateMerger :', ->
 			@folder = _id: @folder_id
 			@fileName = "file.png"
 			@fsPath = "fs/path.tex"
-			@editorController.addFile = sinon.stub().callsArg(5)
+			@editorController.addFileWithoutLock = sinon.stub().callsArg(5)
 			@editorController.replaceFile = sinon.stub().callsArg(4)
-			@editorController.deleteEntity = sinon.stub()
-			@editorController.mkdirp = sinon.stub().withArgs(@project_id).callsArgWith(2, null, [@folder], @folder)
+			@editorController.deleteEntityWithoutLock = sinon.stub()
+			@editorController.mkdirpWithoutLock = sinon.stub().withArgs(@project_id).callsArgWith(2, null, [@folder], @folder)
 			@updateMerger.p.writeStreamToDisk = sinon.stub().withArgs(@project_id, @file_id, @update).callsArgWith(3, null, @fsPath)
 
 		it 'should replace file if the file already exists', (done)->
 			@updateMerger.p.processFile @project_id, @file_id, @fsPath, @path, @source, =>
-				@editorController.addFile.called.should.equal false
+				@editorController.addFileWithoutLock.called.should.equal false
 				@editorController.replaceFile.calledWith(@project_id, @file_id, @fsPath, @source).should.equal true
 				done()
 
 		it 'should call add file if the file does not exist', (done)->
 			@updateMerger.p.processFile @project_id, undefined, @fsPath, @path, @source, =>
-				@editorController.mkdirp.calledWith(@project_id, "folder/").should.equal true
-				@editorController.addFile.calledWith(@project_id, @folder_id, @fileName, @fsPath, @source).should.equal true
+				@editorController.mkdirpWithoutLock.calledWith(@project_id, "folder/").should.equal true
+				@editorController.addFileWithoutLock.calledWith(@project_id, @folder_id, @fileName, @fsPath, @source).should.equal true
 				@editorController.replaceFile.called.should.equal false
 				done()
 
@@ -129,7 +147,7 @@ describe 'UpdateMerger :', ->
 
 		beforeEach ->
 			@path = "folder/doc1"
-			@editorController.deleteEntity = ->
+			@editorController.deleteEntityWithoutLock = ->
 			@entity_id = "entity_id_here"
 			@entity = _id:@entity_id
 			@projectLocator.findElementByPath = (project_id, path, cb)=> cb(null, @entity, @path)
@@ -141,20 +159,20 @@ describe 'UpdateMerger :', ->
 
 		it 'should delete the entity in the editor controller with type doc when entity has docLines array', (done)->
 			@entity.lines = []
-			mock = sinon.mock(@editorController).expects("deleteEntity").withArgs(@project_id, @entity_id, "doc", @source).callsArg(4)
+			mock = sinon.mock(@editorController).expects("deleteEntityWithoutLock").withArgs(@project_id, @entity_id, "doc", @source).callsArg(4)
 			@updateMerger.deleteUpdate @project_id, @path, @source, ->
 				mock.verify()
 				done()
 
 		it 'should delete the entity in the editor controller with type folder when entity has folders array', (done)->
 			@entity.folders = []
-			mock = sinon.mock(@editorController).expects("deleteEntity").withArgs(@project_id, @entity_id, "folder", @source).callsArg(4)
+			mock = sinon.mock(@editorController).expects("deleteEntityWithoutLock").withArgs(@project_id, @entity_id, "folder", @source).callsArg(4)
 			@updateMerger.deleteUpdate @project_id, @path, @source, ->
 				mock.verify()
 				done()
 
 		it 'should delete the entity in the editor controller with type file when entity has no interesting properties', (done)->
-			mock = sinon.mock(@editorController).expects("deleteEntity").withArgs(@project_id, @entity_id, "file", @source).callsArg(4)
+			mock = sinon.mock(@editorController).expects("deleteEntityWithoutLock").withArgs(@project_id, @entity_id, "file", @source).callsArg(4)
 			@updateMerger.deleteUpdate @project_id, @path, @source, ->
 				mock.verify()
 				done()