Since a lot of years I has used Thunderbird for working with more email accounts with some thousands of e-mails. POP3 and iMAP accounts, too. I has store e-mails in different folders in a data partition of my mashine instead of storing them in the system partition. It could be configured in Thunderbird. I use PClinuxOS on the PC. After updating to 60.8 version of Thunderbird the program can not reach the data partition with my e-mails and does not work. Firefox has the same problem, but other applications do not have any problems using this partition.