Hi Maeve,
Since you already did every steps in the mentioned thread, the only place you can find would be depend on whether you turn on the AutoSave toggle (top-left of the PowerPoint window, next to the file name) at any point.
If you forgot to save your workbook after turning off AutoSave, there’s still a chance to recover your work using PowerPoint’s AutoRecover feature or by checking for temporary files. Here are a few steps you can try:
- Check “Recover Unsaved Workbooks” in PowerPoint
- Open PowerPoint. Go to File > Open
- At the bottom of the Recent Workbooks list, click Recover Unsaved Workbooks
- In the dialog box that appears, look for files with extensions like .pptx or .ppt, even .asd files.
- Select the appropriate file and click Open
- Save the file immediately using File > Save As to your desired location

If this method doesn’t show your file, you can manually check the default folder: C:\Users<YourUsername>\AppData\Local\Microsoft\Office\UnsavedFiles
- Search in Windows Temporary Folder
Sometimes PowerPoint stores temporary versions of your file in the system temp folder:
- Open File Explorer
- Type %TEMP% in the address bar and press Enter
- Look for files starting with ~ or ending in .tmp
- Rename the file extension to .pptx and try opening it in PowerPoint. If successful, save it immediately as a new file.
If none of these steps work, please let me know your PowerPoint version and whether you were working on a local file or one stored in OneDrive or SharePoint. I’ll be happy to help further.