VM 1911.17.5
No IDE
ESP 8266 Arduino Core 2.6.1
VS Community 2017 - 15.9.7
Board: NodeMCU12E

Uploading a sketch works pretty smooth, but uploading data to the SPIFFS (4MB Flash, FS:1MB OTA) with "Publish server data files (spiffs)" fails.
Here is the uploader output:

ESP8266FSUpload.exe
## recipe.wwwfiles.upload.pattern
"c:\program files (x86)\microsoft visual studio\2017\community\common7\ide\extensions\y4ur5orx.hne/ESP8266FSUpload.exe"
-serial.port=COM6
Release"
-target_platform="esp8266"
266\tools\mkspiffs\2.5.0-4-b40a506"
-board.name="NodeMCU 1.0 (ESP-12E Module)"
-upload.verbose=True
-upload.resetmethod=--before default_reset --after hard_reset
-upload.speed=115200
sp8266\2.6.1"
-project.name="SomeApp.ino" -project.path="C:\Users\yxz\MyPrj\ESP8266\SomeApp\SomeApp\SomeApp"
python3\3.7.2-post1/python3"
-runtime.tools.esptool.path="{runtime.tools.esptool.path}"
sa-lx106-elf-gcc\2.5.0-4-b40a506/bin/"
-build.spiffs_start="0x300000"
-build.spiffs_end="0x3FA000"
-build.spiffs_pagesize="256"
-build.spiffs_blocksize="8192"
-network.password={network.password}
-network.auth_upload={network.auth_upload}
-network.port={network.port}
C:\Users\yxz\MyPrj\ESP8266\SomeApp\SomeApp\SomeApp\data\config.html
C:\Users\yxz\MyPrj\ESP8266\SomeApp\SomeApp\SomeApp\data\favicon.ico
SPIFFS Creating Image...
[SPIFFS] data   : C:\Users\yxz\MyPrj\ESP8266\SomeApp\SomeApp\SomeApp\data
[SPIFFS] size   : 1000
[SPIFFS] page   : 256
[SPIFFS] block  : 8192
0a506\mkspiffs.exe"
-c "C:\Users\yxz\MyPrj\ESP8266\SomeApp\SomeApp\SomeApp\data"
-p 256 -b 8192
-s 1024000 c9242e9def5bd4d57cabb7b33b51/SomeApp.ino.spiffs.bin"
/config.html
/favicon.ico
SPIFFS Uploading Image...
[SPIFFS] upload : 9242e9def5bd4d57cabb7b33b51/SomeApp.ino.spiffs.bin
[SPIFFS] address: 0x300000
[SPIFFS] reset  : --before
[SPIFFS] port   : COM6
[SPIFFS] speed  : 115200
[SPIFFS] python   : python.exe
[SPIFFS] uploader : ls\upload.py
"python.exe" ols\upload.py" --chip esp8266 --port COM6 --baud 115200 write_flash 0x300000 c9242e9def5bd4d57cabb7b33b51/SomeApp.ino.spiffs.bin" --end
usage*: esptool write_flash [-h] [--erase-all]
   [--flash_freq {keep,40m,26m,20m,80m}]
   [--flash_mode {keep,qio,qout,dio,dout}]
   [--flash_size FLASH_SIZE]
   [--spi-connection SPI_CONNECTION] [--no-progress]
   [--verify] [--encrypt]
SPIFFS Upload failed!
   [--ignore-flash-encryption-efuse-setting]
   [--compress | --no-compress]
   <address> <filename> [<address> <filename> ...]

esptool write_flash*: error: argument <address> <filename>: Must be pairs of an address and the binary filename to write there
 

The spiffs bin file is created correctly and running an upload using

ls\esptool>python esptool.py --port COM6 write_flash 0x300000 9242e9def5bd4d57cabb7b33b51/SomeApp.ino.spiffs.bin 

works without any problems.

But VM ist using the P script

ls\upload.py
 

for both uploading up the sketch (that works well) and for uploading the spiffs bin file. It looks like upload.py creates an unvalid command line for esptool.py when uploading spiffs. 
Or causes ESP8266FSUpload.exe the problem? Unfortunately I dont know much about the toolchain dependencies...

Any hints?

BTW.: I got no issues when using the ESP8266 2.5.2 Arduino Core,

Thanks for your quick response!
I've got no Arduino IDE installed.

Tim@Visual Micro wrote on Nov 28^th, 2019 at 11:57am:

Yep - using esptool.py from the commandline is my current way to upload the spiffs bin file. Well, I don't have to upload spiffs very often, so that's ok for me.

Thank you for your reply!