This is a really strange bug. I am using Office 365 (latest version) Excel and have a series of worksheets set up. One worksheet has over 140 lines and I have Consitional Formatting set up for each line, To save time, I have copied the formatting across from a seperate worksheet to copy across the Conditional Formatting rules. However, as the worksheet I am trying to fix has more lines than what I have copied from, I am having to go in and mnually edit each of the subsequent lines using ConditionalFormatting - Manage Rules. Whilst this is laborious, it works for about 5 lines and then the edit string locks me out so I am unable to edit and have to save my work, shuit down and restart Excel - then everythig continues to work for the next 4 or 5 lines. I then have to repeat the same process just editinting 5 lines at a time. Any ideas?