why do some illustrator files save as capital letters extension

[beharat76828605674yfi4]

why do some illustrator and other adobe program files save as capital letters extensions? Typically they save as .ai, .psd, .ind, etc, but sometimes I see them as .AI, .IND, .PSD etc and with no thumbnail preview. The lowercase files display thumbnail previews with the correct Widnows image codecs but none of them display previews for the uppercase extensions, even file viewers such as Faststone and xnview. 

[Met1]

Are they from UNIX or MS-DOS?

[beharat76828605674yfi4]

what does UNIX/MS-DOS have anything to do with Adobe?

files preview fine as lowercase ai but not always AI but for some reason save as capital AI rather than ai. 

[Monika Gause]

All those files have been saved to the same volume?

[beharat76828605674yfi4]

yes. 

[Monika Gause]

And you created all of those files? Or did you build on someone else's files? Or templates?

None of the folders is a synchronized folder?

And the operating system also hasn't been updated?

[beharat76828605674yfi4]

these are files all created by me, the files are created by adobe products and never capitalized extension, nothing is synchronized, the operating system 'hasn't been updated has nothing to do with this. it is an ADOBE ISSUE.

[Monika Gause]

No need to shout in here. This is a community forum, 95% of people are not staff (staff can easily be recognized, because they are marked as "Staff").

Nobody can look inside your head or into your computer, so we have to ask.

[beharat76828605674yfi4]

no one is shouting. it's good practice to use common sense, unfortunately, people in this generation have lost that ability.

[Anubhav M]

Hello @beharat76828605674yfi4,

We understand that encountering technical issues can be frustrating. I was unable to replicate this behavior on my end. Would you mind confirming if the folder location where you are trying to save the files from Illustrator is a removable/network drive or a cloud-synced folder (Dropbox/Google Drive etc.)? If yes, kindly try saving to a local folder on your computer, like the desktop, and check if it helps. Also, try running Illustrator under a different administrator account (Windows / macOS) and sharing your observations.

Looking forward to hearing from you.

Thanks,

Anubhav