Adobe Digital Editions does not sync across devices

THIS IS STILL AN ISSUE IN MARCH 2021. Embarassing Customer support. The app doesn't do what it says it does, yall shouldn't expect customers if you aren't going to pay any attention to them.

This is ridiculous! Nearly FIVE years after this problem was reported and it still DOES NOT WORK! What a joke! 

I am using Adobe Digital Editions on two Apple devices (one iMac one MacBook), having both computers authorised with my Adobe ID. Technically it should be expected that all the highlights I am making while reading the books of my digital library are displayed on both devices. But it isn't so, and there is also no feature to sync manually. By and large among the digital reading apps ADE is by far the poorest in terms of general usabilty and especially in terms of syncing. I have avoided it as much as possible but sometimes acsm-format is still around. I really hope I can leave behind ADE as soon as possible but find it still embarassing that a big company like Adobe offers such a poorly thought through and poorly working tool, which obviously also nobody there seems to care about at all (issues reported here in 2016 are unresolved in 2021).

Mi último problema con adobe es que tengo un problema en el idioma español que he convertido videos de youtube al español https://convertidor.live/, pero luego no se reproduce correctamente.

Another solution:

1. C:\Users\"Your user"\Documents\My Digital Editions
2. Select your ebook *format PDF
3. Copy and paste it in your phone, tablet, or another device
4. Download it in another device tablet or phone
5.Open your file PDF in your Adobe Digital editions  (previously authorized with the same Adobe ID)

For what it's worth, I deleted the app from my iPhone and reinstalled it immediately. I opened settings in the app and signed back in to authorize using my Adobe ID and all of my books synced to the iPhone. I don't know about future books, but for now it looks like this worked.

I know it's a 4 year old post and I'm sure someone else has probably posted this somewhere in the n pages of replies (I didn't read them all), but hopefully this helps someone.

Sharing the original (acsm) file with the other device worked for me!

Hello to all, as I can see there will not be any solution, see here:

https://helpx.adobe.com/digital-editions/kb/transfer-ebook-ereader-digital-editions.html#

It says:

Only physical eReader devices can sync with Adobe Digital Editions. If you are using an eReading application (iOS or Android), contact the publisher of that application for assistance.

April 24. 2020 - still no solution 😞

I just tried to sync a file from one mac to another, and realized the files are not syncing from the cloud. I needed to email myself a copy of the .ACSM file (the ereader version of a PDF) and then I dragged that file into the ADE on my other computer. And voila, it worked.