[General Questions and Answers] dialman:
I have swapped my older microSD card (64GB) for a larger newer one (256GB), both are formatted as external SD with the exFAT file system (so it can be read with a computer using a microSD card reader for faster and easier file transfers).

The swap initially appeared to be a success, with photos and videos taken with the Samsung stock camera app able to be stored on the new external card. A third party video recorder also worked the same on the new card as it did on the old one (able to select a specific folder and saves properly). Playing back and accessing content from the new card worked fine in a variety of applications (accessing file types: various videos, audio mp3 and FLACs, .PDF, .doc, .epub, .cbz, etc.)

Unfortunately some apps will simply not work, while others which needed to have save locations redirected returned surprising effects.

Titanium Backup v8.1.0 simply does not launch with the new card (returns error Unfortunately, Titanium Backup has stopped.) I have tried first clearing cache and then even uninstalling/re-installing the app - no dice. I swap back to the old card and all works fine. This is the failure that smarts the most as it breaks my phone's app backup plan.

Zedge v5.70.3 app launches and seems to work until I go to install anything to the phone (ringtone, notification sound or wallpaper), then I get a Download failed error and the chosen item is not added. There is no way to swap the download location for the new card. Again I have cleared cache, un-inistalled and re-installed without success. I have sent them a support ticket.

Call Recorder Pro v 1.9 (Tohsoft) required me to change the ''Location of recording'' folder to SD card (no choice of which folder) and this selection resulted in a totally different and complex directory structure used on the new card:

/storage/emulated/0/Android/data/com.tohsoft.call.autocallrecorder.pro/files/CallRecorders

while on the old card I was able to use a more sensibly located folder in the root of the microSD card as follows:

/storage/6958-0839/CallRecorders

As the app works and the files can be retrieved this is not a deal breaker, but it is an added hassle now to locate the recordings!

I checked both cards using ES File Explorer and in the folder

/storage

they each show up as different folder names

old card: 6958-0839

new card: 0102-1A79

A bit of poking around searching online and I determined these were the unique volume IDs and not the volume names. Apparently these can be changed on a PC but I am unsure if this would have other implications. I also looked around for symlinking (which I use on my PCs to map my NAS shares), to see if a virtual link could be made to fool the operating system into thinking the cards were the same one. There was some info about this but I am not sure where I would put the symlink if the file system allows me to create it (on FAT file systems such as the microSD card's one this is a no no apparently, but I do not know the file system of internal memory where the link to the external SD would need to be - I wonder, is it using one of the Linux Ext file systems that support symlinks?)

I was guessing that a symlink for the new card named 6958-0839 (to look like my first working microSD card) should be placed in the following folder (after selecting Device in ES File Explorer):

/mnt/media_rw/

My handset is a Samsung Galaxy Note 4 N910U Android 6.0.1 stock rooted

I have tried searching here about this issue without success. Apologies if I am asking something that has already been answered - please direct me accordingly in this case.

Any assistance will be greatly appreciated.