Attach original files and recover failed uploads

Check storage and access first

Files are stored in the team's connected Slack workspace, not in web-only file storage. You need active team access in the selected company. Ask a team owner to connect an active Slack installation and link the intended channel; Slackalendar needs channel access and the required Slack file permissions. For private channels, invite the app in Slack. Your access to open a stored file also depends on Slack permissions.

Stage files while creating a task

1. 01Open New Task from My Tasks or a team page, or start a task from Calendar. Select the intended team and complete any required task fields.
2. 02Choose Attach files and select one or more local files. Review the staged names and sizes; remove a selection with its × control before saving if needed.
3. 03Choose Create Task once. The task is saved first; the staged files then upload individually to that saved task. A staged file count is not proof of a confirmed attachment.
4. 04Open the saved task's Files tab and check which files appear. If some uploads fail, keep the saved task and use the recovery steps below instead of creating it again.

Use the paperclip or Files tab on a saved task

1. 01Open the saved task. Where shown, the inline paperclip labeled Attach file selects one local file for immediate upload.
2. 02Alternatively, open Files → Attach a file and select a file. Wait for the upload to finish before selecting it again.
3. 03Check the Files list for the attachment. Use its open-in-Slack icon when available; Slack may ask you to sign in or require workspace/channel file access.
4. 04Use the attachment's × delete control only when it should be removed from the task. This removes the task attachment record; it does not promise deletion of Slack's stored copy or any downloaded copies.

File types, originals and size limits

• Each file can be up to 10 MB (10 × 1024 × 1024 bytes). The limit is per file, not the total of the staged selection. Larger files are rejected.
• The file picker does not restrict extensions or MIME types. CAD originals such as .3mf, .3MF, .f3d and .F3D can be selected without converting, extracting or renaming them.
• Slackalendar forwards the original selected filename and bytes to Slack. A thumbnail or icon is not a converted replacement for the original. Slack permissions and service availability still determine whether the upload and opening succeed.

Recover after an upload failure

1. 01If the app says the task was created but files could not be uploaded, do not create the task again. Find the saved task in its team or with sidebar search.
2. 02Open Files and check for partial success: some staged files may have attached while others failed. Creation-time selections are cleared after the upload attempts; choose missing files again from the saved task.
3. 03Check the 10 MB per-file limit, selected company, active team access, Slack installation, linked channel and Slackalendar's channel/file permissions. Ask a team owner to correct the connection if needed.
4. 04An upload can reach Slack but fail confirmation afterward. A failed confirmation does not prove Slack has no copy. Check the intended Slack channel with an authorized teammate before retrying, to avoid duplicate copies.
5. 05After resolving the cause, retry only missing files from Files → Attach a file or the inline paperclip. Do not retry while a request is pending. Check the resulting list and link rather than assuming a click succeeded.