I cannot upload a file

Almost every failed upload is one of three things: the format, the size, or a photo from an iPhone.

What CardCloser accepts

The iPhone problem

By default, newer iPhones save photos as HEIC. On your phone it looks like an ordinary photo. It is not a format CardCloser accepts, and the failure is often silent-looking because nothing about the file suggests a problem.

1. Open Settings on your iPhone.
2. Go to Camera, then Formats.
3. Choose Most Compatible. New photos are saved as JPEG.
4. For a photo you already have, open it in Photos, and share or export it — sharing usually converts it to JPEG on the way out.

Other causes

The file is over 10 MB.

A photo straight from a good camera often is. Export a smaller version, or email it to yourself and use the resized copy.

The file is a PDF, a Word document or a screenshot recording.

Only images are accepted. Export a frame or a page as an image.

The file has the wrong extension for its contents.

Renaming a HEIC to .jpg does not convert it. Re-export properly.

You are on a slow or dropping connection.

A 9 MB upload on poor mobile signal can time out. Try on Wi-Fi.

Your browser is blocking the file picker.

Try a different browser. Some privacy extensions interfere with file selection.

If none of this works

1. Note the file type and roughly its size.
2. Note which upload control you were using.
3. Use Report a problem and include both.