All my Dropbox files have suddenly become online-only and I get an error 0x800701AA on Windows.

Hey espenkarlsen, thanks for posting on our forum and welcome aboard.

Did you start receiving this error all of a sudden on your computer or was there any sort of update before this started happening? 

Have you tried any other steps in the meantime, like reinstalling the app, and the error remains? 

Finally, are you getting this error when copying/moving any file in your local Dropbox folder? 

Let me know once you have more updates.

Hi! This happened all of a sudden and I noticed the preferences had changed to cloud only. I changed it back but today I was cloud only again? No updates lately. 

I see, thanks for clarifying that! Did you also try reinstalling the Dropbox app and there’s still no option to make your files available offline?

I reinstalled the app but it seems Sync switch to online-only without my activation. I have to have References open, then nothing happens. Today the external drive where Dropbox is located disconnected without my knowledge. Now it's indexing 225,317 files..... I'm not  happy with what is going on! 

Can you please right-click on the local Dropbox folder, as the next step, go to its Properties and send me a screenshot of the next window you’ll see?

Hi espenkarlsen, could you provide the screenshot my colleague requested showing the properties of the Dropbox folder on your machine?

Thanks for the image, it looks like you have over 300,000 files in your Dropbox folder, which could be causing this issue. 

Could you first try right clicking the Dropbox folder and choosing the option to make all files available offline?