In that first screenshot you posted it shows the details of just the job. In the bottom window on the left side where the one line is in “Pending” status if you click that then it will change the right side window and more details.  In here it should show what tape it is waiting on.

The status in the main job window about waiting for tape is all you will see, you need to check the job status at the bottom of the screen to see which tape it wants.

For me, it looks like you want to write files to tape. And the library is waiting for a new/or free tape. 

If I take a look at your screenshots, I see that you don’t have any tape currently online/inserted. 
If you have some in your library, which are free - place them in the corresponding pool, or mark them as free. 
 

edit: as you are using a TL, don’t worry about which tape you have to enter in your case. Just have some online, in the correct pools, or in the free pool. If they are in the correct pool, not write protected due to retention, VBR could use them (depends on your settings). 
I don’t care if it’s written on tape X or Y, VBR will handle it. 
 

best, Markus

Thats correct, but the aim is, not to insert all tapes of a media pool to get the job done, i want the specific label name of the tape so i don’t always have to play the tape jockey when only 2 or 3 tapes of overall 24 of i.e. this media pool are needed.

I just want to insert the needed one, not the whole media pool.

For now i’m missing that information.

I see, i never tried that.

I’ll power on the whole infrastructure now and test that.

Keep in mind it might say it needs a tape but if that tape and others are part of the data backup you may need more than just one.  Keep us posted.

You’re my hero, that worked.

The situation is now that i’ve insered the first tape, the tape library scanned the bar code and the media pool also sees the first needed tape. But the backup job still waits for the tape and nothing happens. I thought the tape robot will grab the tape now and insert it into the drive as usual. Do i always have to rescan the library from veeam when i insert a tape while a job waits? I hope not. This usually isn’t needed when i put all tapes from the media pool into the tape library before the job starts.

No you should not have to scan it each time loading a tape but this to me means that more than one tape is required for the “SET” to begin the backup process.  Glad to hear this helped out.

Usually it takes 2 tapes running the job. As you can see for now only 000064L5 is required which is already online in the media pool. No information about a 2nd tape for now and it still waits.

Tape backup is not one of the fastest with Veeam and I know saying be patient is not what anyone wants to hear but I find that it will eventually sort itself out and start.  If you want to try scanning you can to see if that gives it a kick to go.

Also are you using 12.3 which is the latest release and has improvements to tape?

I’m fine with the speed. It hangs for at least 0,5h waiting for tape already. Rescanning the library didn’t help. If there’s another practical option to give it a kick i’d test that. Waiting for so long hoping it requires the next tape to start or even accept the first insered one is no option cause the job will take forever. Yes i’m using 12.3.0.310.

Well see how it goes but if a problem you may want to reach out to Support as a last step to see if they can find anything wrong.  Best of luck.

Do you know if there’s a manual way to tell a job to go ahead?

I don’t have a support contract, i’m sorry. So this isn’t an option for me .

No other than cancelling the job and re-running it again there is no way to force it unfortunately. 

But that would ruin the plan to only insert the tapes that are needed for the job, as the story would repeat itself from the beginning.
I have the feeling that after your helpful information I am almost at the finish line, I just need to give the thing a little nudge.

Well if you figure out what the nudge is let me know and what works. 

I think it works.
I found out that Veeam has a 72 hour timeout for "waiting for tape".
That made me look for registry entries for it.
I found two keys. One for hours, another for minutes.
First, believing that 72 hours was too long and that's why it wouldn't work, I set the DWORD WaitForValidTapeTimeoutMin (Decimal) key under HKEY_LOCAL_MACHINE\SOFTWARE\Veeam\Veeam Backup and Replication to 1 minute and started the job again.
Of course, that went completely wrong, because the timeout had already been reached before I could insert the tape, the tape library could catalog it, and then use a rescan under Veeam to transfer the tape library from an offline to an online status so that the tape could then be pulled into the drive via the robot.
Although that went wrong, it gave me two answers when handling it. Namely, that the tape library logically carries out a new indexing for the magazine after each magazine in/out, but Veeam switches the tape library offline during this time and leaves it that way, even if the tape library is already finished. I never noticed this at the time because I had already fully loaded the tape library with the indexing ready before the Veeam server was started up. It also showed me that when handling the tape library after indexing, the tape library under Veeam has to be brought back online manually with a rescan, otherwise the job will wait to death.
Well, on the second attempt I set the timeout to 5 minutes. That was better. The first host address was processed, the tape was pulled into the drive immediately after I brought the tape library back online. The almost 60GB took more than 5 minutes, which is probably why the second host address did not run through correctly. Windows Server 2025 also gives a message that Veeam is waiting for a tape, but nothing more. So the whole job ran through with the first host, somehow not properly with the second, but still with success, but overall a job warning.
So I thought at the end, before I start fine-tuning the waiting for tape timeout, I wanted to go back to the standard, because I think I didn't follow the order with the rescan.
So I deleted the registry key, got the tape from the tape library and started the job again.
The tape was requested this way too, after indexing the tape library I revived the library from offline to online with a rescan in Veeam, and this time the job ran without a hitch for both hosts.
The tape was also ejected cleanly at the end, as before.
Unfortunately, this time there was no data in the sense of a change, but no matter, the job ran as expected.
In all the tests, only one tape was requested. I still have to produce more data in different places to see if the process works with more than one tape request, and above all in which order with which magazine.
Because if a tape is in the drive after being requested and the second one is already being requested, I can only eject all the left or all the right magazines with 48 slots, each with 12 slots per magazine, and two magazines per side. I will see how that works with the indexing while Veeam writes to one tape but then the library has to be brought back online with a rescan because of the indexing.
Maybe I should activate the mail slots for up to 3 tapes in quick access. Then I don't always have to process an entire magazine. We'll see, I'm on the right track, I've been helped a lot, thanks again!

So much stuff to go through but glad you have seemed to figure things out.  Always here to help out.