Resolving the fonts to question marks in Safari and Mail issue
Since upgrading to Sierra, on my merry way through upgrading my mac to get as up to date as I can, I have found that Safari and Mail are showing loads of question marks instead of words. Obviously its a font issue and the fonts that should be displayed are maybe not being found to be rendered as they are.
I have scoured the forums a bit to see if I can find a resolution. I haven't read anything which explains things fully.
I am not using font Book application and am unsure how fonts are managed without font book or other font management software installed.
I had installed Font Explorer X to manage fonts but have also deactivated it and this has little to no bearing on the rendering of the actual fonts. When font explorer x is activated then when opening up and using safari and mail I get repeated requests for fonts which are not activated, many of which are not on my system. Fonts such as Google Sans, Paypal Sans, Myanmar Sangam MN, Market sans are names which appear. Its rather erratic and I am trying to comprehend what the issue is in order to resolve it.
I did find a temporary solution in Font Explorer X cleaning the system font cache. I got this message also (See image) and was wondering if this offers insight into what the issue is. Once the cache is cleared then a restart is required and this can give a short term solution until the Mac goes to sleep during periods of inactivity. Once re awakened then the question marks reappear.
Any experts out there able to offer any insights at all?
Many thanks for any positive contributions.
Mac Pro, macOS 10.12