Claude Opus 4.6 Troubleshooting Manual: Endless Loading Spinner, Login Issues, and Attachment Failures

If Claude Opus 4.6 keeps spinning without producing a result, shows an error, or won’t upload attachments, it’s usually not that “the model is broken,” but rather network issues, browser cache, account sessions, or usage-triggered limits. Below is a practical, scenario-based troubleshooting checklist to help you pinpoint the cause and get back to using it within minutes.

Start with three basic troubleshooting steps: status, network, session

Step 1: Check service status first: open status.anthropic.com. If there’s a widespread outage, don’t keep refreshing—waiting for recovery is more time-efficient. Step 2: Troubleshoot the network: try switching Wi‑Fi/mobile hotspot, or change to a different route and then log in again. Many “won’t load/keeps spinning” issues are caused by an unstable connection.

Step 3: Troubleshoot the session: log out and log back in once, and clear site cache and cookies (clearing only the Claude site is enough). If you have multiple chat tabs open at the same time, close the extra pages first to avoid sessions competing with each other and causing apparent lag.

Endless loading spinner / send failures: browsers and extensions are common culprits

For this type of issue, start troubleshooting with the browser: open Claude Opus 4.6 in Incognito/Private mode. If it works normally, cache or an extension is interfering. Common “culprits” are ad blockers, script managers, and privacy/anti-tracking extensions—they may block requests and prevent messages from being sent.

For further troubleshooting, test with a clean browser (either Chrome or Edge is fine) and update it to the latest version. If your company network uses a proxy or HTTPS inspection, it can also cause Claude Opus 4.6 requests to fail; switching to a phone hotspot is often a quick way to verify.

Login anomalies and frequent logouts: account and verification troubleshooting

When troubleshooting login issues, first confirm you’re using the same login method (email/Google/Apple) and don’t switch back and forth, which can lead to “session not found.” If you see repeated redirects or you’re logged out immediately after logging in, it’s usually related to cookie policies or third-party login popups being blocked. Allow popups and disable strict “prevent cross-site tracking,” then try again.

If you log in frequently across multiple devices, Claude Opus 4.6 may require re-verification—this is not a malfunction. During troubleshooting, try completing verification on a single device first, then return to your usual device to log in; the success rate is higher.

Attachment upload failures and parsing errors: troubleshoot starting with the file itself

For attachment issues, check the file first: switch to more common formats (PDF/PNG/JPG/TXT), avoid special symbols in the filename and overly long paths, and compress the file to a smaller size before trying again. If the upload progress bar gets stuck, disable cloud-drive extensions and download-manager extensions first—they sometimes take over the upload flow.

If the same file repeatedly fails in Claude Opus 4.6, consider splitting the content into multiple smaller files or pasting the text in sections—this is the fastest troubleshooting workaround. If it still doesn’t work, screenshot the on-page error message and submit a support request along with your browser version and network environment for faster diagnosis.