Don't worry too much about losing IMEI, there are ways to recover it, here Mytour.vn will guide you how to backup and restore IMEI on Samsung Galaxy without Root.
A - Backup IMEI for Samsung Galaxy
Step 1 : Download NV Items Reader Writer Tool then extract it.
Step 2 : Download and install USB Driver for Samsung on your computer.
Step 3 : Enable USB Debugging on your device
Step 4 : Open the dialer and dial *#7284#
Step 5 : Select Qualcomm USB Settings
Step 6 : Connect your phone to the computer via USB cable and run the tool NV-items_reader_writer.exe as Administrator
Step 7 : Go to the Port tab and select your samsung serial port.
Step 8 : Check both 2 BOTH options at the top middle.
Step 9 : Press Connect.
Step 10 : Click Read on the top bar.
Step 11 : Click Read below in the ‘NV-items‘ box.
Step 12 : Save the file as .txt. This is your backup file.
Step 13 : Dial *#7284# and select Qualcomm USB Settings then check MTP + ADB.
B - Restore IMEI.
Click Write below in the NV-items box and select your Backup file.
https://Mytour.vn/sao-luu-va-phuc-hoi-imei-dien-thoai-samsung-galaxy-khong-can-root-1592n.aspx
So we've guided you on how to backup and restore IMEI for Samsung Galaxy phones without root, once done, your device should operate normally as before.