user120435: I run Bitcon Core under windows 10. I have now set up a docker container to run Bitcoin Core under linux on the windows computer. I copied the windows bitcoin directory (containing all the blockchain data) to another directory and mapped the docker container to it.
Launching the docker container Bitcoin Core starts its initial download as if the data is not already there.
Can anyone think of any reason the windows data would not be acceptable to the docker/linux app?

user120435: Doh! I had the mapping for the directory wrong in the docker file. It has now started up and is verifying the blocks.
I would delete the question, but knowing this works may be useful to someone.

120435: <p>I run Bitcon Core under windows 10. I have now set up a docker container to run Bitcoin Core under linux on the windows computer. I copied the windows bitcoin directory (containing all the blockchain data) to another directory and mapped the docker container to it.</p>
<p>Launching the docker container Bitcoin Core starts its initial download as if the data is not already there.</p>
<p>Can anyone think of any reason the windows data would not be acceptable to the docker/linux app?</p>
 120435: <p>Doh! I had the mapping for the directory wrong in the docker file. It has now started up and is verifying the blocks.</p>
<p>I would delete the question, but knowing this works may be useful to someone.</p>
