Thanks for uploading the file!
The first issue I see is that the file has a UTF-16 byte-order-mark. The file is stored as UTF-16 which isn't fully supported in MATLAB. This is why you see the extra boxes between each of the characters.
I did the following to check that your file even needed to be UTF-16--it doesn't.
fid = fopen('Charge4_Probe_3.txt','r','n')
bytes = fread(fid)';
bytes(1:2) = ;
any(bytes(2:2:end) ~= 0)
So none of the characters are using the second byte--effectively this is an ascii file. I'd look into the source of the file and see if you can get it as utf-8 (that will half the file size)
To get a new file, you can write as follows:
asciibytes = bytes(1:2:end)
fid = fopen('Charge4_Probe_3_ascii.txt','w','n','UTF-8');
This is now ready to be read. (Note: as Aquatris mentions, these are using a decimal separator of comma.)
To read this programatically, you can do this:
opts = detectImportOptions('Charge4_Probe_3_ascii.txt','Delimiter','\t');
opts.DataLines = [4,inf];
opts = setvartype(opts,'double');
opts = setvaropts(opts,'DecimalSeparator',',');
T = readtable('Charge4_Probe_3_ascii.txt',opts);
Hope this helps,