gildas-lormeau/SingleFile · error · Error

Cannot access the tab contents

Error message

Cannot access the tab contents

What it means

captureTab throws this when the tab cannot be captured because its contents are not accessible. Tabs like chrome:// pages, the Web Store, other extensions' pages, or discarded/prerendered tabs do not expose content to content scripts, so no capture can run.

Source

Thrown at src/core/bg/business.js:234

		return new Promise((resolve, reject) => {
			const taskInfo = addTask({
				status: TASK_PENDING_STATE,
				tab: {
					id: tab.id,
					index: tab.index,
					url: tab.url,
					title: tab.title
				},
				options: tabOptions,
				method: "content.capture",
				resolve,
				reject
			});
			taskInfo.cancel = () => reject(new Error("SingleFile capture was cancelled"));
			runTasks();
		});
	}
	throw new Error("Cannot access the tab contents");
}

function addTask(info) {
	const taskInfo = {
		id: currentTaskId,
		status: info.status,
		tab: info.tab,
		options: info.options,
		method: info.method,
		resolve: info.resolve,
		reject: info.reject,
		done: function (runNextTasks = true) {
			const index = tasks.findIndex(taskInfo => taskInfo.id == this.id);
			if (index > -1) {
				tasks.splice(index, 1);
				if (runNextTasks) {
					runTasks();
				}

View on GitHub (pinned to 517fb7c5cf)

Solutions

1. Filter out non-capturable URLs (chrome://, about:, Web Store) before calling captureTab
2. Ensure host permissions/content script access is granted for the target URL
3. Activate the tab and check tab.status === 'complete' and a real http(s)/file URL before capture
4. Catch the error and skip or report the tab as non-capturable

Example fix

// before
const results = await Promise.all(tabs.map(t => singlefile.captureTab(t)));
// after
const capturable = tabs.filter(t => /^https?:/.test(t.url || ''));
const results = [];
for (const t of capturable) {
  try { results.push(await singlefile.captureTab(t)); }
  catch (e) { if (e.message === 'Cannot access the tab contents') continue; throw e; }
}

const capturable = tab && tab.id != null && /^https?:/i.test(tab.url || '') && tab.status === 'complete';
if (!capturable) throw new SkipCapture();

const canCapture = (tab) => Boolean(tab && typeof tab.id === 'number' && /^https?:/i.test(tab.url || ''));

try { return await captureTab(tab); } catch (e) { if (e.message === 'Cannot access the tab contents') return skip(tab); throw e; }

When it happens

Trigger: captureTab called on a privileged/protected page (chrome://, edge://, extension pages, Web Store) or a tab without an injectable content script (no host permissions, discarded tab, missing tabId).

Common situations: Batch-capturing all open tabs and hitting restricted browser pages; capturing tabs from other windows/profiles; missing 'tabs' or host permissions in manifest; capturing a discarded tab.

Related errors

• Cannot identify the extension requesting SingleFile capture
• Unauthorized sender
• SingleFile capture was not approved for this extension

AI-assisted analysis of gildas-lormeau/SingleFile@517fb7c5cf (2026-09-01). Data as JSON: /api/errors/302b18770eec286e. Report an issue: GitHub.