Step-by-Step Fix
1) Confirm the exact symptom
Write down the exact message, when it started, and whether it affects one browser/device or everything.
2) Run the two isolation tests
- Incognito/private window
- Second network (phone hotspot, no VPN)
3) Reset browser/session state
- sign out/in
- hard refresh
- clear site data for the Claude site
- disable extensions temporarily
4) Rule out VPN/proxy and network filtering
Disable VPN/proxy and retry once on a stable network.
5) Verify account/workspace context
Confirm you’re using the correct account/workspace for the feature or billing state.
6) Escalate with a clean report
Include: error text, timestamp, region, browser/app + OS, and what you already tested.
Common Root Causes
- stale session/cookies
- extensions blocking requests
- VPN/proxy or network filtering
- wrong account/workspace
- platform-side incident or rollout
Prevention Tips
- keep one clean browser profile for Claude
- avoid rapid retries after errors
- use hotspot + incognito as the first diagnostic step
Why This Happens
When you attach a file to Claude, it is uploaded to Anthropic's servers and converted into tokens before the conversation continues. The "processing" spinner indicates that either the upload itself is still in progress (network-dependent) or the server-side conversion from file format to tokens has not completed. Files get stuck in processing most often when: the network connection is unstable (causing a partial upload), the file is in an unsupported or corrupted format that the conversion pipeline cannot parse, or the file is large (over 5MB) and the conversion is taking longer than the UI timeout expects.
Common Mistakes to Avoid
- Attaching a file and immediately submitting the message. The file must finish processing before Claude can analyze it. Submitting while the spinner is still showing will send the message without the file content, and Claude will respond without any reference to the attachment.
- Uploading files over a slow or cellular connection. File uploads to Claude require a stable connection during the entire upload and processing phase. On a 4G connection with 5–10 Mbps upload speed, a 10MB PDF can take 15–30 seconds to fully upload and process. Switch to Wi-Fi for large file uploads.
- Trying to upload unsupported file types. Attaching a .docx, .xlsx, .zip, or .exe file will cause the processing spinner to spin indefinitely because the conversion pipeline doesn't support those formats. Always convert to PDF, PNG, or plain text before attaching.
- Not refreshing after a stuck upload. If processing is stuck for more than 2 minutes, the upload has likely failed silently. Refresh the page (you will lose your draft message), then re-upload. Do not attempt to submit with a stuck spinner—the attachment will not be included.
- Uploading files larger than 10MB. The maximum supported file size for PDFs is 10MB. Files exceeding this limit will appear to process but will fail silently. Use a PDF compression tool to reduce file size below the limit before re-uploading.
Q: How long does it normally take for Claude to process an uploaded file? For a typical PDF under 5MB, processing takes 5–15 seconds on a stable broadband connection. Larger files (5–10MB) may take 20–45 seconds. Images under 1MB typically process in 2–5 seconds. If the spinner runs for more than 90 seconds, assume the upload has failed and refresh the page before retrying.
Q: Why does my PDF upload fail but an image of the same content works? Claude's PDF extraction pipeline performs OCR and layout parsing, which is more complex than image analysis. Corrupted PDFs, password-protected PDFs, or PDFs generated from scanned images without embedded text may fail the extraction step. Converting the PDF to PNG screenshots (one per page) and uploading the images instead usually bypasses this issue. Alternatively, use a tool like Adobe Acrobat to run OCR on your scanned PDF before uploading.
Q: Is there a way to check if my file processed successfully? After the spinner disappears, hover over the attachment thumbnail in the message input area. A successfully processed file shows a preview or file name without any error indicator. If the attachment shows a red X or an error icon, it failed processing. You can also test by sending a simple message like "What is this document about?" immediately after processing—if Claude cannot reference the content, the file did not process correctly.
Q: Why does a file process correctly on my phone but get stuck on my laptop? The most common cause is a browser extension on your laptop (particularly VPNs, ad blockers, or privacy tools) interfering with the upload request. Try uploading in an incognito window on your laptop with extensions disabled. If it works, identify which extension is causing the issue by re-enabling them one at a time.
Q: Can Claude process password-protected PDFs? No. Password-protected PDFs cannot be parsed by Claude's extraction pipeline because the decryption requires a password that the server cannot provide. Remove the password protection from the PDF using Adobe Acrobat or a free tool like SmallPDF before uploading.
Related Issues
- Claude attachment count limit reached
- Claude request too large context limit
- Browse more fixes in this category
- Browse all Claude issue clusters
Additional FAQ
Q: How do I know if the problem is on my end or the platform's side? Check the platform's official status page first — most services maintain a public status page that shows current incidents and outages. If no incident is posted and the problem only affects your account (not reported widely on Reddit or Twitter), it is likely a local issue. Testing in incognito mode and on a different network also helps isolate whether the problem is browser-specific, network-specific, or account-specific.
Q: Why do hard refresh and regular refresh fix different problems? A regular refresh (F5) reloads the page using cached resources — it does not clear JavaScript bundles, service worker state, or session cookies. A hard refresh (Ctrl+Shift+R or Cmd+Shift+R) bypasses the cache and fetches all resources fresh from the server. Regular refresh fixes transient network hiccups; hard refresh fixes stale cached code. Neither clears cookies or session tokens — for that, you need to clear site data explicitly from browser settings.
Q: When should I contact support versus waiting it out? Contact support immediately if: you were charged but did not receive access, your account was suspended without explanation, or the problem affects billing or data. Wait and retry after 30–60 minutes if: a status page shows an ongoing incident, the error message says 'try again later', or the problem started very recently. For account-specific errors with no platform-wide incident, opening a support ticket is always the right move — document what you tried and include timestamps.
Related Articles
- Claude usage limit reached
- Claude rate limit fix
- Claude blank page white screen
- Claude can't log in fix
Additional FAQ
Q: How do I know if the problem is on my end or the platform's side? Check the platform's official status page first — most services maintain a public status page that shows current incidents and outages. If no incident is posted and the problem only affects your account (not reported widely on Reddit or Twitter), it is likely a local issue. Testing in incognito mode and on a different network also helps isolate whether the problem is browser-specific, network-specific, or account-specific.
Q: Why do hard refresh and regular refresh fix different problems? A regular refresh (F5) reloads the page using cached resources — it does not clear JavaScript bundles, service worker state, or session cookies. A hard refresh (Ctrl+Shift+R or Cmd+Shift+R) bypasses the cache and fetches all resources fresh from the server. Regular refresh fixes transient network hiccups; hard refresh fixes stale cached code. Neither clears cookies or session tokens — for that, you need to clear site data explicitly from browser settings.
Related Articles
- Claude usage limit reached
- Claude rate limit fix
- Claude blank page white screen
- Claude can't log in fix
Additional FAQ
Q: How do I know if the problem is on my end or the platform's side? Check the platform's official status page first — most services maintain a public status page that shows current incidents and outages. If no incident is posted and the problem only affects your account (not reported widely on Reddit or Twitter), it is likely a local issue. Testing in incognito mode and on a different network also helps isolate whether the problem is browser-specific, network-specific, or account-specific.