My unit developed the NO HD disease about 6 weeks ago. Since I use an external drive 99% of the time, I said *&%@ that's just the way it is.
Then, this past Monday, I decided to read the Denon Forum and try to get to the bottom of the issue.
Although the problem is prevalent, and an abundance of fixes appear on the forum, none seemed to address my "problem".
Yesterday, I switched the power on and off several times, and voila, the internal HD is back!
I quickly downloaded the music i had on it,along with some great play lists, and put it all on my external drive. I then tried loading some new music on to the 40Gig internal. I overloaded it and it crashed!! Oh well!
Just for the sake of it, I deleted all of my internal HD music and uploaded 20 gigs worth of my most requested music.
The internal is running well, the search is quick, and there seems to be no problems. Its operating like it did when it was new!
One of the things I discovered is that if you have an abundance of files with that are not acceptable to the Denon format, the had drive can "hic-cup" if you will.
I don't know if I had some bad files, or if the hard drive is dying , or what. But with only 20 gigs on it, it runs nice.
I am going to re-fit the internal with a new 120 gig hard drive. 3 times the storage space, as well as being a new drive.
The Denon HD 2500 should have never been discontinued. It is a great solution for music media playback and mixing. BTW--it is a fantastic re-mixing tool! The hot start buttons, echo. filter, dump, reverse, and brake effects and pitch bend effects are awesome.
The internal hard drive--convenient, but certainly not necessary.