diff --git a/chrome/content/zotero/xpcom/storage/storageEngine.js b/chrome/content/zotero/xpcom/storage/storageEngine.js
index 9ba53726b6..255d8d6d15 100644
--- a/chrome/content/zotero/xpcom/storage/storageEngine.js
+++ b/chrome/content/zotero/xpcom/storage/storageEngine.js
@@ -292,10 +292,19 @@ Zotero.Sync.Storage.Engine.prototype.start = Zotero.Promise.coroutine(function*
 })
 
 
-Zotero.Sync.Storage.Engine.prototype.stop = function () {
-	Zotero.debug("Stopping file sync for " + this.library.name);
-	for (let type in this.queues) {
-		this.queues[type].stop();
+/**
+ * @param {String} [queueToStop] - 'upload' or 'download'; if not specified, stop all queues
+ */
+Zotero.Sync.Storage.Engine.prototype.stop = function (queueToStop) {
+	if (queueToStop) {
+		Zotero.debug(`Stopping file sync ${queueToStop} queue for ` + this.library.name);
+		this.queues[queueToStop].stop();
+	}
+	else {
+		Zotero.debug("Stopping file sync for " + this.library.name);
+		for (let type in this.queues) {
+			this.queues[type].stop();
+		}
 	}
 }
 
@@ -330,9 +339,10 @@ Zotero.Sync.Storage.Engine.prototype.queueItem = Zotero.Promise.coroutine(functi
 	this.queues[type].add(() => {
 		var request = new Zotero.Sync.Storage.Request({
 			type,
+			engine: this,
 			libraryID: this.libraryID,
 			name: item.libraryKey,
-			onStart: request => this.controller[fn](request),
+			onStart: request => this.controller[fn](request, this),
 			onStop: () => {
 				this.requestsRemaining--;
 				this.onProgress(this.numRequests - this.requestsRemaining, this.numRequests);
diff --git a/chrome/content/zotero/xpcom/storage/storageLocal.js b/chrome/content/zotero/xpcom/storage/storageLocal.js
index cf084196cb..4b50b767be 100644
--- a/chrome/content/zotero/xpcom/storage/storageLocal.js
+++ b/chrome/content/zotero/xpcom/storage/storageLocal.js
@@ -9,6 +9,10 @@ Zotero.Sync.Storage.Local = {
 	SYNC_STATE_FORCE_DOWNLOAD: 4,
 	SYNC_STATE_IN_CONFLICT: 5,
 	
+	// If last-known remaining storage is below this number of megabytes, skip further upload
+	// attempts in various situations
+	STORAGE_REMAINING_MINIMUM: 5,
+	
 	lastFullFileCheck: {},
 	uploadCheckFiles: [],
 	storageRemainingForLibrary: new Map(),
diff --git a/chrome/content/zotero/xpcom/storage/storageRequest.js b/chrome/content/zotero/xpcom/storage/storageRequest.js
index fbbb7ebbaa..573b4ebb91 100644
--- a/chrome/content/zotero/xpcom/storage/storageRequest.js
+++ b/chrome/content/zotero/xpcom/storage/storageRequest.js
@@ -28,6 +28,7 @@
  * Transfer request for storage sync
  *
  * @param {Object} options
+ * @param {Zotero.Sync.Storage.Engine} options.engine
  * @param {String} options.type
  * @param {Integer} options.libraryID
  * @param {String} options.name - Identifier for request (e.g., "[libraryID]/[key]")
@@ -36,16 +37,18 @@
  * @param {Function|Function[]} [options.onStop]
  */
 Zotero.Sync.Storage.Request = function (options) {
+	if (!options.engine) throw new Error("engine must be provided");
 	if (!options.type) throw new Error("type must be provided");
 	if (!options.libraryID) throw new Error("libraryID must be provided");
 	if (!options.name) throw new Error("name must be provided");
-	['type', 'libraryID', 'name'].forEach(x => this[x] = options[x]);
+	['engine', 'type', 'libraryID', 'name'].forEach(x => this[x] = options[x]);
 	
 	Zotero.debug(`Initializing ${this.type} request ${this.name}`);
 	
 	this.callbacks = ['onStart', 'onProgress', 'onStop'];
 	
 	this.Type = Zotero.Utilities.capitalize(this.type);
+	this.engine = options.engine;
 	this.channel = null;
 	this.queue = null;
 	this.progress = 0;
diff --git a/chrome/content/zotero/xpcom/storage/zfs.js b/chrome/content/zotero/xpcom/storage/zfs.js
index 9d9990f9de..0d3e0a9f73 100644
--- a/chrome/content/zotero/xpcom/storage/zfs.js
+++ b/chrome/content/zotero/xpcom/storage/zfs.js
@@ -284,6 +284,11 @@ Zotero.Sync.Storage.Mode.ZFS.prototype = {
 				}
 			}
 			if (skip) {
+				// Stop trying to upload files if there's very little storage remaining
+				if (remaining < Zotero.Sync.Storage.Local.STORAGE_REMAINING_MINIMUM) {
+					Zotero.debug(`${remaining} MB remaining in storage -- skipping further uploads`);
+					request.engine.stop('upload');
+				}
 				throw yield this._getQuotaError(item);
 			}
 		}
@@ -294,7 +299,22 @@ Zotero.Sync.Storage.Mode.ZFS.prototype = {
 				return new Zotero.Sync.Storage.Result;
 			}
 		}
-		return this._processUploadFile(request);
+		
+		try {
+			return yield this._processUploadFile(request);
+		}
+		catch (e) {
+			// Stop trying to upload files if we hit a quota error and there's very little space
+			// remaining. If there's more space, we keep going, because it might just be a big file.
+			if (e.error == Zotero.Error.ERROR_ZFS_OVER_QUOTA) {
+				let remaining = Zotero.Sync.Storage.Local.storageRemainingForLibrary.get(item.libraryID);
+				if (remaining < Zotero.Sync.Storage.Local.STORAGE_REMAINING_MINIMUM) {
+					Zotero.debug(`${remaining} MB remaining in storage -- skipping further uploads`);
+					request.engine.stop('upload');
+				}
+			}
+			throw e;
+		}
 	}),
 	
 	
@@ -607,7 +627,7 @@ Zotero.Sync.Storage.Mode.ZFS.prototype = {
 			}
 			
 			// Store the remaining space so that we can skip files bigger than that until the next
-			// manual sync
+			// manual sync. Values are in megabytes.
 			let usage = req.getResponseHeader('Zotero-Storage-Usage');
 			let quota = req.getResponseHeader('Zotero-Storage-Quota');
 			Zotero.Sync.Storage.Local.storageRemainingForLibrary.set(item.libraryID, quota - usage);
diff --git a/test/tests/zfsTest.js b/test/tests/zfsTest.js
index e64597701c..afdfd2a2a6 100644
--- a/test/tests/zfsTest.js
+++ b/test/tests/zfsTest.js
@@ -74,9 +74,10 @@ describe("Zotero.Sync.Storage.Mode.ZFS", function () {
 	
 	var setup = Zotero.Promise.coroutine(function* (options = {}) {
 		Components.utils.import("resource://zotero/concurrentCaller.js");
+		var stopOnError = options.stopOnError !== undefined ? options.stopOnError : true;
 		var caller = new ConcurrentCaller(1);
 		caller.setLogger(msg => Zotero.debug(msg));
-		caller.stopOnError = true;
+		caller.stopOnError = stopOnError;
 		
 		Components.utils.import("resource://zotero/config.js");
 		var client = new Zotero.Sync.APIClient({
@@ -93,7 +94,8 @@ describe("Zotero.Sync.Storage.Mode.ZFS", function () {
 				apiClient: client,
 				maxS3ConsecutiveFailures: 2
 			}),
-			stopOnError: true
+			background: options.background,
+			stopOnError
 		});
 		
 		return { engine, client, caller };
@@ -802,6 +804,75 @@ describe("Zotero.Sync.Storage.Mode.ZFS", function () {
 			var result = yield engine.start();
 			assert.equal(called, 4);
 		});
+		
+		
+		it("should stop uploading files on quota error", async function () {
+			var { engine, client, caller } = await setup({ stopOnError: false });
+			
+			var numItems = 4;
+			var items = [];
+			for (let i = 0; i < numItems; i++) {
+				let item = await importFileAttachment('test.png');
+				item.version = 5;
+				item.synced = true;
+				await item.saveTx();
+				items.push(item);
+			}
+			
+			var requests = 0;
+			server.respond(function (req) {
+				if (req.method == "POST"
+						&& req.url.startsWith(`${baseURL}users/1/items/`)
+						&& req.url.endsWith('/file')
+						&& req.requestBody.indexOf('upload=') == -1
+						&& req.requestHeaders["If-None-Match"] == "*") {
+					requests++;
+					req.respond(
+						413,
+						{
+							"Content-Type": "application/json",
+							"Last-Modified-Version": 10,
+							"Zotero-Storage-Usage": "300",
+							"Zotero-Storage-Quota": "300"
+						},
+						"File would exceed quota (299.7 + 0.5 > 300)"
+					);
+				}
+			})
+			
+			await engine.start();
+			assert.equal(requests, Zotero.Prefs.get('sync.storage.maxUploads'));
+			
+			Zotero.Sync.Storage.Local.storageRemainingForLibrary.delete(items[0].libraryID);
+		});
+		
+		
+		// If there was a quota error in a previous run and remaining storage was determined to be
+		// very low, stop further file uploads for a background sync even when we bail without an
+		// HTTP request. A manual sync clears the remaining-storage value.
+		it("should stop uploading files for background sync if no storage remaining after previous quota error", async function () {
+			var { engine, client, caller } = await setup({ background: true, stopOnError: false });
+			
+			var numItems = 4;
+			var items = [];
+			for (let i = 0; i < numItems; i++) {
+				let item = await importFileAttachment('test.png');
+				item.version = 5;
+				item.synced = true;
+				await item.saveTx();
+				items.push(item);
+			}
+			
+			Zotero.Sync.Storage.Local.storageRemainingForLibrary.set(items[0].libraryID, 0);
+			
+			var spy = sinon.spy(engine.controller, 'uploadFile');
+			await engine.start()
+			
+			assert.equal(spy.callCount, Zotero.Prefs.get('sync.storage.maxUploads'));
+			spy.restore();
+			
+			Zotero.Sync.Storage.Local.storageRemainingForLibrary.delete(items[0].libraryID);
+		});
 	})
 	
 	
@@ -830,7 +901,7 @@ describe("Zotero.Sync.Storage.Mode.ZFS", function () {
 			
 			var request = { name: item.libraryKey };
 			
-			var stub = sinon.stub(zfs, '_processUploadFile');
+			var stub = sinon.stub(zfs, '_processUploadFile').returns(Zotero.Promise.resolve());
 			await zfs.uploadFile(request);
 			
 			var zipFile = OS.Path.join(Zotero.getTempDirectory().path, item.key + '.zip');
@@ -1057,7 +1128,7 @@ describe("Zotero.Sync.Storage.Mode.ZFS", function () {
 							"Zotero-Storage-Usage": "300",
 							"Zotero-Storage-Quota": "300"
 						},
-						"File would exceed quota (299.7 + 0.5 &gt; 300)"
+						"File would exceed quota (299.7 + 0.5 > 300)"
 					);
 				}
 			})
@@ -1073,7 +1144,8 @@ describe("Zotero.Sync.Storage.Mode.ZFS", function () {
 			
 			// Try again
 			var e = yield getPromiseError(zfs.uploadFile({
-				name: item.libraryKey
+				name: item.libraryKey,
+				engine
 			}));
 			assert.ok(e);
 			assert.equal(e.errorType, 'warning');