IssacChan I tried installing PHP v7.2 and updating the 4 fields mentioned above in the php.ini, but the results were the same. Below 50Kb files will upload, above sizes will not.
You said to make sure I have the plug-in for attachments installed/set up, are you referring to the osTicket plug-in, or something related to PHP/IIS/Windows/etc? I have the osTicket plug-in installed and pointed to save files to the "C:\osTicketAttachments" dir. That folder has read/write/execute permissions for the IUSR and IIS_IUSR group, which looks like it should be the one being used by IIS/PHP. Additionally, files are being written to that folder, so I am making the presumption it is working properly.
One thing I did find odd, but may be the way it is supposed to work, is that once a file is uploaded via osTicket and saved to the attachments folder, they are not retaining their file name or extension. Files will be uploaded from osTicket and automatically saved to a seemingly random subdirectory, with a seemingly random alphanumeric file name and no file extension. Example: A user uploads a test.txt file as an attachment, the file appears as "C:\osTicketAttachments\K\K2LPYTE37-luVBK_YeF_NJ_rp2jin1NQ" where the K subdirectory is automatically chosen/created, and the "K2LPYTE37-luVBK_YeF_NJ_rp2jin1NQ" portion represents the filename with no file extension. It is still a 1Kb file, but is not saved as a any specific file type. Opening the file with Notepad will still work/show the text, only the name/extension appears to be obfuscated/randomized/removed. Can this be turned off so that it is saved as the original file type at least, in case I want to manually backup the file elsewhere?