diff --git a/packages/core/src/api.js b/packages/core/src/api.js
index 7fac93237..5b8310260 100644
--- a/packages/core/src/api.js
+++ b/packages/core/src/api.js
@@ -18,6 +18,7 @@ export function createPercyServer(percy, port) {
 
       // return json errors
       return next().catch(e => res.json(e.status ?? 500, {
+        build: percy.build,
         error: e.message,
         success: false
       }));
diff --git a/packages/core/src/percy.js b/packages/core/src/percy.js
index 7cc5c1309..f98b472ec 100644
--- a/packages/core/src/percy.js
+++ b/packages/core/src/percy.js
@@ -168,7 +168,8 @@ export class Percy {
     // handle deferred build errors
     if (this.deferUploads) {
       buildTask.catch(err => {
-        this.log.error('Failed to create build');
+        this.build = { error: 'Failed to create build' };
+        this.log.error(this.build.error);
         this.log.error(err);
         this.close();
       });
@@ -281,7 +282,7 @@ export class Percy {
     if (this.build?.failed) {
       // do not finalize failed builds
       this.log.warn(`Build #${this.build.number} failed: ${this.build.url}`, meta);
-    } else if (this.build) {
+    } else if (this.build?.id) {
       // finalize the build
       await this.client.finalizeBuild(this.build.id);
       this.log.info(`Finalized build #${this.build.number}: ${this.build.url}`, meta);
@@ -311,10 +312,9 @@ export class Percy {
   snapshot(options) {
     if (this.readyState !== 1) {
       throw new Error('Not running');
-    }
-
-    // handle multiple snapshots
-    if (Array.isArray(options)) {
+    } else if (this.build?.error) {
+      throw new Error(this.build.error);
+    } else if (Array.isArray(options)) {
       return Promise.all(options.map(o => this.snapshot(o)));
     }
 
@@ -351,6 +351,10 @@ export class Percy {
 
   // Queues a snapshot upload with the provided options
   _scheduleUpload(name, options) {
+    if (this.build?.error) {
+      throw new Error(this.build.error);
+    }
+
     return this.#uploads.push(`upload/${name}`, async () => {
       try {
         /* istanbul ignore if: useful for other internal packages */
@@ -367,6 +371,7 @@ export class Percy {
 
         // build failed at some point, stop accepting snapshots
         if (failed) {
+          this.build.error = failed.detail;
           this.build.failed = true;
           this.close();
         }
diff --git a/packages/core/src/queue.js b/packages/core/src/queue.js
index 25bdf28d3..9551f859b 100644
--- a/packages/core/src/queue.js
+++ b/packages/core/src/queue.js
@@ -15,9 +15,8 @@ export class Queue {
   }
 
   push(id, callback, priority) {
-    if (this.closed && !id.startsWith('@@/')) {
-      throw new Error('Closed');
-    }
+    /* istanbul ignore next: race condition paranoia */
+    if (this.closed && !id.startsWith('@@/')) return;
 
     this.cancel(id);
 
diff --git a/packages/core/test/api.test.js b/packages/core/test/api.test.js
index afd001d09..79518d427 100644
--- a/packages/core/test/api.test.js
+++ b/packages/core/test/api.test.js
@@ -155,7 +155,11 @@ describe('API Server', () => {
 
     let [data, res] = await request('/percy/snapshot', 'POST', true);
     expect(res.statusCode).toBe(500);
-    expect(data).toEqual({ success: false, error: 'test error' });
+    expect(data).toEqual({
+      build: percy.build,
+      error: 'test error',
+      success: false
+    });
   });
 
   it('returns a 404 for any other endpoint', async () => {
@@ -163,7 +167,11 @@ describe('API Server', () => {
 
     let [data, res] = await request('/foobar', true);
     expect(res.statusCode).toBe(404);
-    expect(data).toEqual({ success: false, error: 'Not Found' });
+    expect(data).toEqual({
+      build: percy.build,
+      error: 'Not Found',
+      success: false
+    });
   });
 
   it('facilitates logger websocket connections', async () => {
diff --git a/packages/core/test/percy.test.js b/packages/core/test/percy.test.js
index 161920458..9c5c9ef1b 100644
--- a/packages/core/test/percy.test.js
+++ b/packages/core/test/percy.test.js
@@ -363,7 +363,7 @@ describe('Percy', () => {
       expect(() => percy.snapshot({
         name: 'Snapshot 2',
         url: 'http://localhost:8000'
-      })).toThrowError('Closed');
+      })).toThrowError('Failed to create build');
 
       expect(logger.stdout).toEqual([
         '[percy] Percy has started!',
@@ -374,6 +374,47 @@ describe('Percy', () => {
         '[percy] Error: build error'
       ]);
     });
+
+    it('stops accepting snapshots when an in-progress build fails', async () => {
+      mockAPI.reply('/builds/123/snapshots', () => [422, {
+        errors: [{
+          detail: 'Build has failed',
+          source: { pointer: '/data/attributes/build' }
+        }]
+      }]);
+
+      // create a new instance with default concurrency
+      percy = new Percy({ token: 'PERCY_TOKEN', snapshot: { widths: [1000] } });
+      await percy.start();
+
+      await Promise.all([
+        // upload will eventually fail
+        percy.snapshot({
+          url: 'http://localhost:8000/snapshot-1'
+        }),
+        // should not upload
+        percy.snapshot({
+          url: 'http://localhost:8000/snapshot-2',
+          // delay this snapshot so the first upload can fail
+          waitForTimeout: 100
+        })
+      ]);
+
+      await percy.idle();
+
+      expect(logger.stderr).toEqual(jasmine.arrayContaining([
+        '[percy] Encountered an error uploading snapshot: /snapshot-1',
+        '[percy] Error: Build has failed'
+      ]));
+
+      expect(mockAPI.requests['/builds/123/snapshots'].length).toEqual(1);
+
+      // stops accepting snapshots
+      expect(() => percy.snapshot({
+        name: 'Snapshot 2',
+        url: 'http://localhost:8000'
+      })).toThrowError('Build has failed');
+    });
   });
 
   describe('#stop()', () => {
diff --git a/packages/core/test/snapshot.test.js b/packages/core/test/snapshot.test.js
index 7e96aea0e..35ca717ee 100644
--- a/packages/core/test/snapshot.test.js
+++ b/packages/core/test/snapshot.test.js
@@ -45,18 +45,16 @@ describe('Snapshot', () => {
   });
 
   it('warns when missing additional snapshot names', async () => {
-    percy.close(); // close queues so snapshots fail
-
-    expect(() => percy.snapshot({
-      url: 'http://foo',
+    await percy.snapshot({
+      url: 'http://localhost:8000',
       additionalSnapshots: [{
-        waitForTimeout: 1000
+        waitForTimeout: 10
       }, {
         name: 'nombre',
         suffix: ' - 1',
-        waitForTimeout: 1000
+        waitForTimeout: 10
       }]
-    })).toThrow();
+    });
 
     expect(logger.stderr).toEqual([
       '[percy] Invalid snapshot options:',
@@ -65,10 +63,8 @@ describe('Snapshot', () => {
     ]);
   });
 
-  it('warns when providing conflicting options', () => {
-    percy.close(); // close queues so snapshots fail
-
-    expect(() => percy.snapshot({
+  it('warns when providing conflicting options', async () => {
+    await percy.snapshot({
       url: 'http://a',
       domSnapshot: 'b',
       waitForTimeout: 3,
@@ -77,7 +73,7 @@ describe('Snapshot', () => {
       additionalSnapshots: [
         { prefix: 'f' }
       ]
-    })).toThrow();
+    });
 
     expect(logger.stderr).toEqual([
       '[percy] Invalid snapshot options:',
@@ -88,10 +84,8 @@ describe('Snapshot', () => {
     ]);
   });
 
-  it('warns if options are invalid', () => {
-    percy.close(); // close queues so snapshots fail
-
-    expect(() => percy.snapshot({
+  it('warns if options are invalid', async () => {
+    await percy.snapshot({
       name: 'invalid snapshot',
       url: 'http://localhost:8000',
       widths: ['not-a-width'],
@@ -103,7 +97,7 @@ describe('Snapshot', () => {
           'finally.a-real.hostname.org'
         ]
       }
-    })).toThrow();
+    });
 
     expect(logger.stderr).toEqual([
       '[percy] Invalid snapshot options:',
@@ -114,12 +108,12 @@ describe('Snapshot', () => {
     ]);
   });
 
-  it('warns on deprecated options', () => {
-    percy.close(); // close queues so snapshots fail
-
-    expect(() => percy.snapshot({ url: 'http://a', requestHeaders: { foo: 'bar' } })).toThrow();
-    expect(() => percy.snapshot({ url: 'http://b', authorization: { username: 'foo' } })).toThrow();
-    expect(() => percy.snapshot({ url: 'http://c', snapshots: [{ name: 'foobar' }] })).toThrow();
+  it('warns on deprecated options', async () => {
+    await percy.snapshot([
+      { url: 'http://localhost:8000/a', requestHeaders: { foo: 'bar' } },
+      { url: 'http://localhost:8000/b', authorization: { username: 'foo' } },
+      { url: 'http://localhost:8000/c', snapshots: [{ name: 'foobar' }] }
+    ]);
 
     expect(logger.stderr).toEqual([
       '[percy] Warning: The snapshot option `requestHeaders` ' +
diff --git a/packages/sdk-utils/src/post-snapshot.js b/packages/sdk-utils/src/post-snapshot.js
index f7db54024..cf1ef7734 100644
--- a/packages/sdk-utils/src/post-snapshot.js
+++ b/packages/sdk-utils/src/post-snapshot.js
@@ -7,7 +7,7 @@ export async function postSnapshot(options, params) {
   let query = params ? `?${new URLSearchParams(params)}` : '';
 
   await request.post(`/percy/snapshot${query}`, options).catch(err => {
-    if (err.response && err.message === 'Closed') {
+    if (err.response?.body?.build?.error) {
       percy.enabled = false;
     } else {
       throw err;
diff --git a/packages/sdk-utils/test/helpers.js b/packages/sdk-utils/test/helpers.js
index c909bbdba..da2258c6a 100644
--- a/packages/sdk-utils/test/helpers.js
+++ b/packages/sdk-utils/test/helpers.js
@@ -17,7 +17,7 @@ const helpers = {
   teardown: () => helpers.call('server.close'),
   getRequests: () => helpers.call('server.requests'),
   testReply: (path, reply) => helpers.call('server.reply', path, reply),
-  testFailure: (path, error) => helpers.call('server.test.failure', path, error),
+  testFailure: (...args) => helpers.call('server.test.failure', ...args),
   testError: path => helpers.call('server.test.error', path),
   testSerialize: fn => !fn
     ? helpers.call('server.test.serialize') // get
diff --git a/packages/sdk-utils/test/index.test.js b/packages/sdk-utils/test/index.test.js
index 3fc10d02d..60f4593e2 100644
--- a/packages/sdk-utils/test/index.test.js
+++ b/packages/sdk-utils/test/index.test.js
@@ -118,7 +118,8 @@ describe('SDK Utils', () => {
     });
 
     it('returns false if a snapshot is sent when the API is closed', async () => {
-      await helpers.testFailure('/percy/snapshot', 'Closed');
+      let error = 'Build failed';
+      await helpers.testFailure('/percy/snapshot', error, { build: { error } });
       await expectAsync(isPercyEnabled()).toBeResolvedTo(true);
       await expectAsync(utils.postSnapshot({})).toBeResolved();
       await expectAsync(isPercyEnabled()).toBeResolvedTo(false);
@@ -162,8 +163,9 @@ describe('SDK Utils', () => {
     });
 
     it('disables snapshots when the API is closed', async () => {
+      let error = 'Build failed';
       utils.percy.enabled = true;
-      await helpers.testFailure('/percy/snapshot', 'Closed');
+      await helpers.testFailure('/percy/snapshot', error, { build: { error } });
       await expectAsync(postSnapshot({})).toBeResolved();
       expect(utils.percy.enabled).toEqual(false);
     });
diff --git a/packages/sdk-utils/test/server.js b/packages/sdk-utils/test/server.js
index 280736f5e..02874e669 100644
--- a/packages/sdk-utils/test/server.js
+++ b/packages/sdk-utils/test/server.js
@@ -72,8 +72,8 @@ function context() {
       test: {
         get serialize() { return serializeDOM; },
         set serialize(fn) { return (serializeDOM = fn); },
-        failure: (path, error) => ctx.server.reply(path, () => (
-          [500, 'application/json', { success: false, error }])),
+        failure: (path, error, o) => ctx.server.reply(path, () => (
+          [500, 'application/json', { success: false, error, ...o }])),
         error: path => ctx.server.reply(path, r => r.connection.destroy()),
         remote: () => (allowSocketConnections = true)
       }