Cannot group image and caption together

osto1017 

I have experienced this exact same problem and found the solution (albeit too late for you, it might be useful to others, or future me).

This issue arises when the Word document was opened and saved with a different (older) version of Word than you currently are using. When opened with a more recent version of windows, the document then goes into 'compatibility mode' and changes some object types.

In my case I had figures (Wrap Text: square) with captions (object: shape format) and grouped them together to make sure they stay together. After it was opened and saved by an older version of Word, the corners of the box around the caption was showing grey squares instead of open circles (exaclty as you show in your figures), and I was unable to group captions. Ungrouping a previously grouped figure and caption lead to two ungroupable objects. It turns out the object type of the caption was changed from being a 'shape format' to a 'text box', caused by the compatibility settings, and this object type cannot be grouped with a 'picture format'. To undo this, go to 'File'→'info'→'convert', the latter option being a big button visible as the big square with the word logo on the left-hand side in the area named 'compatibility mode'. Note this might change some of the layout of the document. After this the caption by default is of the object type 'shape format' again (this is shown in the ribbon at the top right) and is groupable with figures again (iff figures are wrapped not being 'in-line with text' but something else).

TLDR: An older version of Word was used before, causing the document to go into compatibility mode. Go to 'File'→'info'→'convert', the latter option being a big button visible as the big square with the word logo on the left-hand side in the area named 'compatibility mode'. A popup gives a warning the layout might change, click 'OK'. Now captions are groupable with figures again.