File Upload and Attachment Errors

Attachment problems fall into three buckets: the upload never completes, the file uploads but won’t preview, or the file exists but someone can’t open it. Each has a different cause, so identify your bucket first and jump to the matching section.

”Upload Failed” or Upload Stuck at 99%

1. Check the file size against your plan limit — 25 MB per file on Free, 250 MB on Pro and Business. The uploader rejects oversized files, but some browsers show a generic failure instead of the size message. Check your limit under Settings > Workspace > Plan
2. Rename the file to remove unusual characters — #, %, and emoji in filenames break some upload paths. Stick to letters, numbers, dashes, and underscores
3. An upload stuck at 99% is the post-upload virus scan, not the transfer. Wait 30 seconds; if it never resolves, refresh and retry
4. On flaky connections, large uploads time out silently. Retry on a wired or stronger connection, or compress the file into a .zip
5. If every upload fails regardless of size, a browser extension is likely intercepting requests — retry in an incognito window with extensions off

Blocked File Types

For security, Loomstack rejects executable formats: .exe, .bat, .cmd, .sh, .msi, and similar. To share one legitimately (for example, an installer build for QA):

1. Compress it into a .zip archive, which is allowed
2. Or upload it to Google Drive/Dropbox and attach the link instead — linked files aren’t subject to type restrictions

Workspace admins on Business plans can customize the blocklist under Settings > Workspace > Security > Attachment rules.

File Uploaded but Preview Is Broken

1. Previews render for images, PDFs, and common office formats. Anything else (e.g., .psd, .fig, .zip) shows a download-only card by design
2. A gray box where an image should be usually means the preview is still generating — files over ~20 MB can take a minute. Refresh the task
3. If a PDF preview shows blank pages, the PDF likely uses an embedded font the renderer can’t handle; the download itself is unaffected
4. Corrupted previews on one device but not others point to a local cache problem: clear site data for app.loomstack.app and reload

Teammates Can’t Open a Drive or Dropbox Attachment

Linked cloud files keep their original permissions — Loomstack never widens access:

1. The viewer should click Request Access on the file, which routes through Google’s or Dropbox’s normal sharing flow
2. Better: the file owner should move shared files into a team drive or shared folder before attaching
3. Watch for the yellow Limited access badge when attaching — it warns you at attach time that some project members can’t see the file. Click it to fix sharing immediately

Attachment Disappeared from a Task

1. Check the task’s Activity log (three dots > Activity) — it records who removed an attachment and when
2. Removing an attachment only unlinks it; direct uploads go to the workspace Trash (Settings > Workspace > Trash) and are restorable for 30 days
3. For linked cloud files, deletion in Drive/Dropbox breaks the card in Loomstack. Restore the file from the cloud provider’s own trash and the link revives

Summary

Upload failures are nearly always size limits, blocked file types, odd filenames, or an interfering extension — incognito mode is the fastest differential test. Broken previews usually resolve with time or a cache clear, and access problems on Drive/Dropbox links are fixed by the file’s owner widening sharing, not in Loomstack. Deleted attachments can be recovered from the workspace trash within 30 days.