I understand this upload might be stuck. Dropbox has your files saved on the cloud and the files you have not uploaded yet will remain safe in the local Dropbox folder you have on your desktop, even if this folder is not connected to Dropbox. So reinstalling would not affect this folder.
I hope this helps with your concern. Let's start with unlinking and relinking the Dropbox desktop app from your folder. This will reset your configuration settings. Please find the steps to do this here.
Did this post help you? If so, please give it a Like below. Did this post fix your issue/answer your question? If so please press the 'Accept as Solution' button to help others find it. Still stuck?Ask me a question!(Questions asked in the community will likely receive an answer within 4 hours!)