Official sources reviewed · October 3, 2026
When a Grok file upload fails, first ask whether the attachment failed to arrive, failed to load, or loaded but produced a poor answer. Those outcomes call for different checks. Start with one harmless small file on the same account, then change only one variable.
Grok web and mobile upload rules
| Published scope | xAI guidance | Boundary to remember |
|---|---|---|
| Documents, images, code and audio | Most files: up to 150 MB each | Do not extend this wording to every video workflow |
| Web batch | Up to approximately 100 files | Approximate, not a guarantee for every batch |
| Android batch | Up to 20 files | A different client route |
| iOS batch | Multiple files; no fixed count given | Do not invent a number |
The Grok FAQ lists common documents, code, images, audio and video; GIF/SVG support varies by platform. Embedded pictures in non-PDF documents may not be analyzed visually. Long PDFs can be handled selectively, and media transcription quality varies. These are consumer web/app rules, not developer API input limits.
The same FAQ points to the web file manager for stored content and Settings → Usage for weekly allowance information. Those are different problems: removing a stored document does not establish that a time-based allowance reset.
A useful three-file diagnostic set
Create your own non-sensitive controls rather than uploading an internal report repeatedly:
- Small TXT: two sentences containing a unique label and a checkable number.
- Simple text PDF: export those sentences from your editor, then confirm the text can be selected locally.
- The affected file: keep the original; test only a permitted copy after the controls.
This is a suggested diagnostic method, not a published HiseHub benchmark. Record attachment state as well as the answer. A successful answer to an ordinary text prompt does not prove the file upload route works.
| Result | Next useful check | Avoid this conclusion |
|---|---|---|
| TXT works; PDF does not | Fresh PDF export, encryption and local extraction | “My paid plan is broken” |
| Both controls work; original fails | Original structure, size, format and batch complexity | “Every upload is down” |
| Same control works on web, not mobile | Client/version and documented platform support | “Buying more credits repairs the file” |
| Attachment is accepted but key evidence is absent | Specific source location and content visibility | “The entire document was read” |
If the transfer stops or the attachment will not load
Confirm that the file opens locally and is completely downloaded. A cloud file placeholder may not contain the bytes you expect; export a local copy only if your organization’s policy permits it. Check the actual byte size rather than a rounded attachment label.
Try the small control in a new conversation. Keep the account, client and network unchanged for the first comparison. If a mobile-only failure persists, use the official web route with the same control. If an approved second route works, record that difference for support rather than deleting the account or changing your payment method.
Do not rename an extension as a substitute for conversion. Export a troublesome document from its original application. For a spreadsheet, preserve a sheet with the relevant headers and rows; a CSV loses formulas, formatting and additional sheets, so use it only when those are not needed.
For media, note whether the file transfers but transcription is wrong. Test a short authorized excerpt containing a known phrase. Container support, transfer success and speech recognition quality are separate questions. Do not publish a transcript as verified merely because the upload finished.
If Grok accepts a PDF but misses details
Use precise references: “PDF viewer page 14, printed page 9, table headed Quarterly Costs.” The old recommendation to use only a printed page number can be ambiguous when a report has a cover or restarts numbering.
Ask for one checkable extraction before a broad summary: the table’s units, the value in a named row, and an exception in the following paragraph. Verify all three in the original. If an answer invents a missing value, reduce the task and request a supporting source location; do not assume a plausible answer establishes complete coverage.
Keep a chart in visual form when its layout carries meaning. Plain text may flatten columns or disconnect a note from the value it qualifies. An image excerpt can also lose nearby context, so include the heading and relevant footnote when you are permitted to share them.
Check PDF text before another attempt
AI File Preflight locally checks PDF/TXT/Markdown extraction, flags low-text or incomplete coverage and produces smaller text chunks. It is not OCR, a Grok tokenizer, a malware scanner, or an account-allowance test. Keep the original and inspect every chunk boundary.
A small text count does not mean an image-heavy PDF is small for Grok. Conversely, compressing the bytes without reducing the relevant text may not solve a context problem. Use the tool to inspect what was extracted, not to certify that Grok will process every original page.
Do not clear storage or buy credits before identifying the gate
If the product specifically reports a storage problem, retain important files before reviewing unneeded stored content. If it reports a usage warning, note the usage/reset display and follow the weekly-limit guide. If paid access is missing, use subscription troubleshooting.
None of those actions repairs a corrupted attachment. Repeated all-at-once changes also erase the evidence of what caused the failure. Do not enable automatic payments or delete an entire history as a troubleshooting shortcut.
Build a support report without exposing the document
Record the exact error, time/timezone, web/iOS/Android client and version, file type and byte size, batch count and the harmless-control result. Note whether it stalls, is rejected immediately or is attached but cannot be loaded. Redact account identifiers from anything posted publicly; use the official support route for account-specific information.
Never include API keys, private documents, access tokens or unredacted browser captures by default. Preserve organizational network/security controls. If every small control fails, a documented account/client/service investigation is more useful than continuing to compress the original.
HiseHub is independent of xAI/X. Official FAQ reviewed October 3, 2026. Account, platform and subscription differences remain; this article does not promise one universal upload count or invent an undocumented video cap.