Start Here: Find the Right File Fix
Two tools for size and transfer planning
File-size calculator: MB, MiB, GB and GiB — compare units.
File transfer time calculator — estimate time using explicit size, speed and usable-rate assumptions. Neither calculator uploads files.
Open or convert a file
Downloaded file is empty or will not open
Check the download before changing applications.
PDF text cannot be selected
Separate scanned pages from text and check OCR output.
Convert HEIC to JPG on Mac
Export a copy while keeping the original.
Before using an online converter
Decide whether your file should leave your device.
Copy, back up or verify
USB says the file is too large
Check file-system limits before formatting.
Verify SHA-256 on Windows
Compare the download with the right reference.
Check a backup restore
Test recovery into a separate folder.
Make OneDrive files available offline
Prepare and test the files you actually need.
Read, organize or send
CSV text is garbled in Excel
Separate encoding, delimiter and data-type issues.
Zip and unzip on Windows
Package files and check the extracted copy.
Use a practical file naming system
Keep dates, subjects and versions recognizable.
Reduce a PDF on Mac
Compare readability before sharing.
Changing a suffix does not change the file format. See why renaming a file extension is not conversion.
Not sure which guide applies?
Write down the exact error, the file extension, your operating system and whether the original opens. A download problem, a file-format problem and a storage-limit problem need different fixes. Avoid repeatedly renaming extensions or uploading the same private file to unfamiliar converters.
Our editorial standards explain what was tested and where the instructions come from. Use Contact & corrections to report an unclear instruction. Do not send private files or passwords.