htaccess overwrite – can't find solution in previous posts

I know there are a lot of posts about htaccess but I can’t find the solution. the htaccess file is overwritten every time I do anything at all in WP. To be clear I have the basic htaccess code – nothing extra added. I am using custom permalinks. I should add that I am also using WPhive to add other blogs – all blogs have the same settings. When the file is overwritten it is basically deleted – it becomes a blank file and therefore the pages don’t display (404) I have made the file read only – although it won’t accept read only for admin which I assume is normal. This is also a common question on the WPHive forum – but can’t get any help there either.

Any suggestions for a permanent solution or workaround would be very welcome.