Hello Hanna Myronova,

I believe this error is generally caused by merging source segments across paragraphs (one or more of which contains an illustration/graphic).

To try to resolve this - go to your source language folder- copy and rename the original source file and then add this to your Studio project.

Now immediately try to 'save target as'.

If this still doesn't work then take the source file and remove the graphic- and re-add the file to the project.

Does this help?

And because there is no "undo" after having merged segments across paragraph breaks, the problem is there once you merged segment with a graphic element or similar. You cannot unmerge these segments and simple splitting of those will not help. The only solution here is to retranslate the file (from the source folder, as Steve suggests) and NOT merging any segments with graphics or similar. Instead, you can copy and paste all the text content in source (via Edit source) into the segment, where the graphic tag is, leaving all other segments filled with 2 spaces for example. This will bring you similar effect to merging - all text content in one segment, but will not break saving as target.

Thanks Jerzy!

Could you please recommend what to do in orderr not to have such issues in future?

Thanks to Steven and Jerzy!

Though I still wonder whether it is possible to find the void segment and how?

thanks, helped indeed.

Thank you Steven and Jerzy fore these useful tips! It's worked for me as well, however painful and improvised this solution may seem.

I have just spent a few hours re-creating my translation (lots of merging and splitting, sorry, not my fault, although the original pdf looked quite neat, it's become a mess once opened in Studio...). And it makes me wonder why this issue which makes it impossible to export your file is not reported in the verifications process (F8) or why Studio doesn't stop you from merging segments you should not, in the first place... Call it foolproofness, if you like, I call it user-friendliness or better, usability. After all, we have been promised in the promotional videos and tutorials that we would be able to not to worry about the format and just concentrate on our translation. I have purchased Studio not long ago, so I still remember...

Anyway, thanks! 

I just had the same problem and really agree with you. Fortunately, my text was short, but still. 

Well, you can either allow merging over paragraph boundaries or deny it. When you merge across paragraphs, you should be aware what it causes. It does need much imagination to see, that this changes the file structure. And in the end of the day we are mature human beings with own responsibility. Pushing this responsibility onto the software vendor is not really fair...
In the past many of us have been requesting the feature of merging over paragraph boundaries. It is delivered and now we start to moan it does not perform... Well, some other software simply does NOT allow merging - no way to change it. If you prefer to work that way, simply switch the feature off—then nothing like this will happen to you. When you work with tools, you do it on your own risk. A knife is sharp, when you cut yourself would you then blame the manufacturer?
Sorry, if this may sound harsh—please bear in mind, English is not my working language and I just try to explain things in this language. There is no hidden meaning in my words nor want I accuse or attack anyone.

In many cases, I absolutely need to merge segments, because the software cuts the sentences in two in a seemingly arbitrary way. I have neve had any saving problems aver using the merging function until now. BTW, this time, the software even cut phrases in two and put other segments inbetween (actually, all sentences of the text are mixed up like a puzzle):

So, I'm sorry to say so, but it's not always the user's fault. I'd suggest a pop-up window ("are you sure... it may lead to..."), because why would you let the user do anything that blocks the "save" function? If I cannot save my text (even with formatting problems in it), it literally does not has any sense.

This is unfortunately a user fault. Your source file has been created in a completely unprofessional way—there should be no paragraph breaks in first place.

But I agree, a warning in case of such segments could be helpful. However, merging across paragraph breaks does not always cause problems. Mostly nothing happens - but here you have tags in your segments, and tags are always to be treated with care.