The tape compartment after ejecting the tape does not slide back to position even after closing the door.

I see your picture of a cassette player. Guess you are referring to that. (tapes also come in reel-to-reel, and 8-track). Just push the "EJECT" button (power may need to be applied to some units for the eject button to work). The tape slot will open. Insert tape with exposed tape on the "head" side of the opening, usually the heads are on the bottom of the slot.. You can't put it in any other way and have the door close. The "door" that opens has guides for you to slide the tape into. The side you want to listen to should face you. Either manually close the tape compartment or push the close button (depending on model). If the door doesn't close, you put it in upside down. Push play and enjoy.

there is a risk of hardware damage.make sure you dont force the tape into the cassette compartment to avoid damage to the unit or tape.here's what you can do.
1.remove the tape from the compartment.
2.ensure proper type and size of tape is used.
3.ensure no packaging material or foreign material inside the compartment.
4.if attempting to record, make sure cassette tape rec/save switch is set to rec position.
5.reinsert the tape, make sure it's properly inserted.
6.if still won't close or tape ejected again,remove tape.
7.reinsert a diff tape.
8.attempt to close compartment.
9.if issue unresolved, press the tiny reset button while cam is powered on (located in the panel where the lcd screen goes to,just below all the other buttons). you may also do a power reset procedure: remove batt, remove ac adaptor,set power switch to vcr, leave the cam without power for at least a minute, switch power back to off, reinsert ac adaptor/batt and turn cam on, attempt to close tape compartment.

if issue persists, service would be needed. hope this helps.thanks:)

you are prohibited from recording on thips tape. This is because the red tab on the side of the tape that faces you when you are inserting the tape inside the camera has been put in 'SAVE' position . to be able to record o the tape you need to use your fingernail to slide the red tab to the 'REC' position.

Ive extracted the following article for you from wilkepedia to help you understand this issue:
Tape and recording protection
The write-protect switch (right) prevents accidental erasure. .
To prevent the recording on the tape from being erased, there is a small write-protect tab that can be moved to one of two positions, labeled "REC" and "SAVE". Comparing the sliding tab to a door, the tape is in the "REC" position is when the "door" is open and the "SAVE" position when it is closed. (Not all tape cases have markings for this information!) The tape can only be recorded on (or recorded over) when this tab is in the "REC" position. This is an improved version of the VHS write-protect tab, which prevents erasure after it has been (permanently) broken off.

Check eject lever near battery, press it downward to open tape compartment, take out old tape and put new tape, close tape door and let it go inside by itself. Close tape compartment.

Below image will help you to locate eject button/ lever in DCR-HC18E camcorder.
Thanks.

Follow this procedure to troubleshoot if the cassette compartment will not open or the tape is stuck and will not eject.
IMPORTANT: If your camcorder model has a RESET button, first try pressing this button. If there is no RESET button, or pressing the button does not resolve the issue, continue with the troubleshooting steps below.

1. Turn off the camcorder.
2. Remove the battery from the camera.
3. Remove the AC power supply from the camera.
4. Slide the power switch on the camera to the VTR , VCR or CAMERA mode for 15 seconds.
5. Slide the power switch back to the OFF position.
6. Connect the AC power supply to the camera.
7. Attempt to open the cassette compartment.

Follow this procedure to troubleshoot if the cassette compartment will not open or the tape is stuck and will not eject.
IMPORTANT: If your camcorder model has a RESET button, first try pressing this button. If there is no RESET button, or pressing the button does not resolve the issue, continue with the troubleshooting steps below.

1. Turn off the camcorder.
2. Remove the battery from the camera.
3. Remove the AC power supply from the camera.
4. Slide the power switch on the camera to the VTR , VCR or CAMERA mode for 15 seconds.
5. Slide the power switch back to the OFF position.
6. Connect the AC power supply to the camera.
7. Attempt to open the cassette compartment.

NOTE: If the issue is still unresolved after completing all of the troubleshooting steps, service may be required .

I had same problem, while transferring media from TRV-16 to DVD, tape would not play, then would not eject. This after transferring several tapes to DVD. I tried several things over the last couple months that did not work before finally getting it open today. It did me no good to remove several of the outer panels that were each held by two "tiny" phillips head screws each. Went to the internet, found your post, also found a post that referred me back to SONY page which follows.......

Follow this procedure to troubleshoot if the cassette compartment will not open or the tape is stuck and will not eject.
IMPORTANT: If your camcorder model has a RESET button, first try pressing this button. If there is no RESET button, or pressing the button does not resolve the issue, continue with the troubleshooting steps below.

1. Turn off the camcorder.
2. Remove the battery from the camera.
3. Remove the AC power supply from the camera.
4. Slide the power switch on the camera to the VTR , VCR or CAMERA mode for 15 seconds.
5. Slide the power switch back to the OFF position.
6. Connect the AC power supply to the camera.
7. Attempt to open the cassette compartment.

"NOTE: If the issue is still unresolved after completing all of the troubleshooting steps, service may be required."

After I did this, I could hear a whirring sound when I hit eject, although nothing came out. While the whirring was going on, I pulled up and out with constant pressure and the cassette holder opened. The tape had jammed apparently as the little protective plastic tape guard was jammed partially open when I pulled the cassette out. Good Luck and don't be afraid to put a little pressure on the door if you can hear the door trying to open.

Now I turn to recovering the tape, but having grown up with cassette decks, don't believe it will be a problem.

IMPORTANT: If your camcorder model has a RESET button, first try pressing this button. If there is no RESET button, or pressing the button does not resolve the issue, continue with the troubleshooting steps below.

1. Turn off the camcorder.
2. Remove the battery from the camera.
3. Remove the AC power supply from the camera.
4. Slide the power switch on the camera to the VTR, VCR or CAMERA mode for 15 seconds.
5. Slide the power switch back to the OFF position.
6. Connect the AC power supply to the camera.
7. Attempt to open the cassette compartment.

I had the exact same problem, and just by dumb luck, I managed to get the tape compartment to pop open after trying hundreds of things. Maybe this will work for you too...who knows??? What I did was to first remove the battery and AC power to "reset" the camera (I guess). I then put the battery back in place and WHILE HOLDING THE CAMERA IN THE UPRIGHT (AS IF USING THE CAMERA FOR VIDEO) POSITION, I pushed the "Open/Eject" latch. VIOLA!!! Like I said, it may be dumb luck, but I haven't had the problem again. It may be that gravity helped to take the stress off the ejecting mechanism...dunno???? BTW, when I was having the problem, the mechanism would "click" 3 or 4 times while trying to move the tape out. Good luck!!! I hope this helps someone!

The most frequent cause of this type situation is not having a power source attached, or a depleted battery pack. Once the power source is available, some models require manually unlatching and opening the cassette compartment cover. When the cover is fully open, the videocassette will eject automatically. Please try the following procedures. 1. Attach the power source to the camcorder correctly or use a fully-charged battery pack. 2. Fully-open the cassette compartment cover until it stops while sliding and holding the OPEN/EJECT switch. The videocassette will eject automatically after a few seconds. If the videocassette still will not eject, seek assistance from a Canon Service Facility.