Measure length often crashes

i realise this nightly is a bit old but i am using it to write a book of traditional music, often a page will consist of more than one "tune" i am splitting them with vertical frames and adding titles, changing key signature etc is all working fine however this type of music often has pick-up measures (anacrusis) either at the start of a tune or tat the start of the second half, whilst assigning a bar a new meter seems to work fine on a new document, often when halfway or so though a document, i.e starting a new tune on the same page muse score will crash, the file will then refuse to allow this action for example adding a pickup bar in 1/4 every time i restart muse score it will crash again. there seems to be a standard problem perhaps a coding conflict ?

any help would be appriciated and please let me know if you need specific data.